University of California WEED CONTROL Research Report

TURF AND ORNAMENTAL CROPS 1972

Division of Agricultural Sciences

Co-operative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, ond United States Deportment of Agriculture co-opero!ing, Dislributed in furtherance of the Acts of Congress of Moy 8, and June 30, 1914. George 8. Alcorn, Director, California Agricultural Extension Service, (NOT FOR PUBLICATION) UNIVERSITY OF CALIFORNIA

Weed Control in Turf and Ornamental Crops 1972

This report contains results of weed control experiments conducted in turf, container and field grown ornamentals during the 1971 season.

Contributing Authors: R. Baskett w. Humphrey s. Besemer E. Johnson c. Elmore T. Kretchun D. Farnham A. Lange B. Fischer w. Mast L. Frey K. Mueller K. Gowans E. Roncoroni D. Hamilton L. Smith

Compiled By: Clyde L. Elmore, Extension Weed Control Specialist University of Celifornia, ~vis, California

The results presented in this report are part of ongoing research projects and should not in any way be interpreted as reconnnendations of the University of California. TABLE OF CONTENTS

Page Herbicide List l

Weed Species Present in Herbicide Tests 2

Ornamental and Turf Species Present in Herbicide Tests 3 Ground Covers 4

Sunnnary 4 1. Herbicide screening in ground covers and turf 5 2. Tolerance of several ornamental ground cover plant 8 species and weed control from preemergence treat­ ments of herbicides and herbicide combinations 3. Tolerance of several ornamental ground cover plant 16 species and weed control from preemergence treat­ ments of herbicides and herbicide combinations 4. Tolerance of several established ground cover 26 species to five postemergence herbicides 5. Annual weed control in nine ground covers with 28 ten herbicides Woody Ornamentals 31

Summary 31 1. OXalis corniculatus control in container grown 32 ornamentals and tolerance of Pinus thunbergii and Raphiolepis indica to several herbicides 2. Control of bittercress with five preemergence 35 herbicides and tolerance on six container grown ornamentals 3. Effect of several herbicides and herbicide 38 combinations on newly planted Eucalyptus cinerea seedlings 4. Control of annual weeds in Eucalyptus cinerea and 40 Myrtus coilllllUnis 'compacta 1 in the field

Christmas Trees

Sunnnary 42 l. Sheep sorrel control in Monterey pines 43 Turf 45 Surmnary 45 1. Control of annual bluegrass in turf 46 2. Crabgrass control in turf 51 3. Tall fescue control in turfgrass 55 4. Postemergence control of Eleusine tristachya in 55 dichondra 1

HERBICIDE LIST Herbicides Appearing in This Report

Common or Manuracturer or Code Name Trade Name Marketin~ A~enci .A-820 Amchem alachlor LASscfID· Monsanto amitrole ammonium sulfate Various Various AN 56477 TORPEDd© Ansul BAS 2903 BASAMAIZE® BASF benefin BALA:rfB) Elanco bensulide BETASA!ifB) Stauffer bromoxynil NU-LAW!ifB), BROMINAL® Amchem cc 1418 Ortho CGA 10832 CIBA-Geigy chloroxuron TENORA!ifB) CIBA-Geigy chlorpropham FURLOE® PPG dalapon DOWPO#ID Dow dicamba · BANVEL® Velsicol diphenamid DYMrrfB> ENIDE® Elanco, Upjohn diuron KA-® DuPont DSMA ANS.AR 184® Ansul endothall ENDOTHAL® Pennwalt fluorodifen PREFORA!ifB) CIBA-Geigy GS 13638 CIBA-Geigy linuron LOROx® DuPont mecoprop (MCPP) MECOPEx® Nor-Am methazole PROBE® Velsicol methyl bromide DOWFUME MC-~ Dow MSMA ANSAR 52simazine PRINCE!® CIBA-Geigy SOIL SERV ~'jID Soil Serv terbacil SINBAR® DuPont terbutol ArzAK!ID Hercules terbutryn IGRA:rfB) CIBA-Geigy trifluralin TREFLA:rfB) Elanco 2,4-D amine Various Various u 27267 Upjohn 2

WEED SPECIES PRESENT IN HERBICIDE TESTS

Broadleaved Weeds

Common Name Latin Name annual sowthistle Sonchus oleraceus asparagus Aster spinosus bittercress Cardamine .£._ligosperma bristly oxtongue Picris echioides Byzantine speedwell Veronica buxbaumii bull mallow Malva nicaeensis California burclover Medicago polymorpha chickweed Stellaria media clover Trifolium ~ common groundsel Senecio vulgaris common lambsquarters Chenopodium album creeping woodsorrel OXalis corniculatus curly dock Rumex crispu.s field bindweed Convolvulus arvensis filaree Erodium sp. fleabane Erigeronsp. henbit Lamium amplexicaule horseweed Coi?:Yza canadensis London rocket Sisymbrium ~ lupine Lupinus sp. mustard Brassicasp. nettleleaf goosefoot Chenopodium murale Prostrate knotweed Polygonum aviculare Prostrate pigweed Amaranthus blitoides purslanE> Portulaca oleracea red sorrel Rumex acetosella scarlet pimpernel Anagallis arvensis shepherds purse Capsella bursa-pastoris spotted spurge Euphorbia maculata vetch Vicia sp. willow Salix sp.

Grasses annual bluegrass Poa annua barnyardgrass Echinochloa crusgalli bearded sprangletop Leptochloa fascicularis berrrrudagrass Cynodon dactylon goosegrass Eleusine tristachya large crabgrass Digitaria sanguinalis smooth crabgrass Digitaria ischaemum tall fescue Festuca arundinaceae wild oats Avena fatua 3

ORNAMENTAL AND TURF SPECIES PRESENT IN HERBICIDE TESTS

Ornamentals

Connnon Name Latin Name

African trailing daisy Osteospermum fruticosum Algerian ivy Hedera canariensis boxleaf veronica Hebe buxifolia carpet bugle AJuga repens Christmas heather Erica canaliculata 'rosea' dichondra Dichondra repens English ivy Hedera helix eucalyptus Eucalyptus cinerea gazania Gazania splendens golden pfitzer juniper Juniperus chinensis pfitzeriana 1aurea' Grevillea noellii iceplant Delasperma alba iceplant Malephora luteolus Indian hawthorne Raphiolepis indica Japanese black pine Pinus thunbergii Japanese boxwood Buxus japonica large leaf iceplant Carpobrotus edule Monterey pine Pinus radiata periwinkle Vinca minor sedum Sedum brevifolium St. Johnswort gypericum cabycinum tams juniper Juniperus sabina tamariscifolia

Turf

bentgrass Asrostis tenuifolia bermudagrass Q,ynodon dactylon Kentucky pluegrass Poa E_ratensis redtop Agrostis ~ 4

SUMMARY Ground Covers

Four extensive preemergence trials were established on newly planted ground cover species at three locations in California.

Several herbicides are promising for use in ground covers with broad spectrum weed control and selectivity on a number of species. Two of the more outstanding new herbicides tested were oryzalin and alachlor.

Oryzalin gave good control of most annual weeds including some plants in the compositae family that previous herbicides were not so effective con­ trolling. Clover was not controlled however. Alachlor was very effective in one trial when sprinkler incorporated on light soil.

The standard herbicides trifluralin, DCPA, nitrofen, and nitralin gave good control on susceptible weeds, thus giving the landscape contractor or home owner excellent herbicides as tools. Although combination~ of nitralin, R 7465, or trifluralin with 0.25- 0.50 lb/A of simazine gave good control, injury was apparent on several newly planted ground cover species. These treatments would be very effective on established ground covers. The herbicides norea, pronamide, and GS 13638 in these tests did not give broad selectivity necessary for these ornamentals.

R 7465 has given good weed control in some·tests; however, in one test tolerant weeds (prostrate pigweed, shepherdspurse) became the dominant plants. In one test when R 7465 was applied two times in one season, full season weed control was achieved with only slight injury to Carpobrotus edule. Dichondra repens and Ajuga repens were very tolerant to R 7465. The herbicide Soil Serv 463® appeared to be relatively safe on most species although some early chlorosis was observed. Weed control was some­ what variable. Early weed control was generally good; however, by 2 months weed populations were rather severe in some tests. In one postemergence control trial,established Vinca minor, !fypericum calycinum, Gazania splendens, Hedera canariensis, Sedum brevifolium, Hedera helix, and to a lesser extent, Carpobrotus edule appeared to show some tolerance, to the herbicides tested. Linuron showed some safety on most species except Carpobrotus edule when applied postemergence at 1 or 2 lb/A. There was more tolerance to MCPP than 2,4-D amine or amino triazole. Bromoxynil severely burned most species a:rter application but regrowth was normal. 5

Herbicide screening in ground covers and turf. Elmore, c. L., w. Humphrey, A.H. Lange. Several herbicides were selected to be evaluated on two ground cover species, Kentucky bluegrass (Poa pratensis) and dichondra at the South Coast Field Station, Tustin. Generally if weed control can be achieved at planting and for approximately 2 to 4 months after planting, ground covers will become established and cover the ground, thus reducing weed competition. The herbicides selected all have preemergence and residual activity.

Four plants each of Malephora luteolus as rooted cuttings and Carpo­ brotus edule as unrooted cuttings were planted September 30, 1970, and dich­ ondra and Kentucky bluegrass were seeded into a moist prepared seedbed in each plot the same day. After planting the trial was sprinkler irrigated, and all subsequent irrigations were with sprinklers. The herbicides were applied October 5,1970, using a CO2 sprayer with 2-8004 Teejet nozzles at 20 psi in an equivalent of 50 gpa water. The sur­ face of the sandy loam soil (analysis: 0.99% o.m.; 58.5% sand; 22.5% silt; and 19.0% clay) was moist at application and the temperature was 750F. Following herbicide application, the trial was irrigated to wash the herbi­ cide from the treated foliage and slightly leach it into the soil. Evaluations for weed control and phytotoxicity to the various plant species were made November 5and December 22, 1970, and May 20, 1971, on most species (Table 1 and 2). Weed Control All herbicides gave good weed control for 2 months in this trial except AN 56477 at 1 lb/A and nitralin at 2 lb/A. With clover, sowthistle, and shepherdspurse as the principal weed species, these herbicides were not as effective. Using 70 percent control as connnercial, at 6 months the methazole, alachlor, NIA 20439 at 8 lb/A and the oryzalin plus nitrofen or oryzalin plus pronamide gave good control. Methazole at 4 lb/A, alachlor at 8 lb/A, and the oryzalin combinations effectively controlled fleabane at 6 months after application. For being sprinkler incorporated, alachlor and oryzalin gave excellent broad spectrum weed control.

!!v:totoxicity No herbicide was safe to use on direct seeded Kentucky bluegrass. Although CGA 10832 and AN 56477 did not completely kill the grass, it was too pbytotoxic. In dichondra NIA 20439 at 2 and 4 lb/A appeared to be safe; however, at 8 lb/A inJury was evident. Methazole at 1 lb/A injured dichondra early (1 and 2 mo.); however, by 6 months, little injury was evident. With the exception of methazole at 1 and 4 lb/A, all herbicides and rates were safe to use on Carpobrotus edule. In the non-weeded control, severe injury was observed on c. edule at 6 months from competition. As indicated by observing the early weed control and lack of injury on Q• edule by most herbicides, it is apparent that by 6 months a 30-50% weed population may be present and still not cause phytotoxicity (Table 1 and 2). 6.

Malephora luteolus is slightly more sensitive to herbicide injury than carpobrotus edule. Methazole at 1 and 4 lb/A was too injurious as was the oryzalin and pronamide combination. From other tests it was apparent that the pronamide was responsible for this injury. Alachlor at 8 lb/A and NIA 20439 at 8 lb/A would also appear to give only marginal safety. The other herbicides and the 2 and 4 lb/A rates of alachlor and NIA 20439 were safe in this trj_al.

Summary

Several new herbicides or herbicide combinations were tested on two ground cover and two turf species at the South Coast Field Station, Tustin. No herbicides were safe to use on direct seeded Kentucky bluegrass and only NIA 20439 appeared to be safe enough to use on direct seeded dichondra.

Several herbicides and herbicide combinations were safe to use on Carpobrotus edule and also gave good weed control. The most promising appeared to be alachlor, NIA 20439) and oryzalin plus nitrofen. Alachlor, NIA 20439, and oryzalin plus nitrofen also would appear to be the most promising herbicides for a preemergence treatment after planting. Table 2. Average phytotoxicity from several herbicides on two ground cover and two turf species.Y

Rate Poa pratensis j Dichondra repens Carpobrotus edule Malephora luteolus Herbicide Lb/A 11 5 7012 22 70 1175770 127~}70 57~0771 11 5 70 12 22 70 5 0 71 11 5 70 12 22 70 5 20/7_1 methazole 1 10.0 9.8 9.0 8.2 1.5 3.2 3.8 1.2 3.5 3.8 1.8 methazole 4 10.0 10.0 10.0 9.8 8.2 7.8 9.5 9.0 9.8 9.5 9.2 CGA 18032 2 6.2 5.8 5.0 8.8 8.2 o.o 0.2 o.o 0.2 o.o 0.5 AN 56477 1 7.5 6.o 4.5 7.8 4.5 0~8 o.o 1.0 0.2 0.5 1.0 AN 56477 4 7.0 5.5 5.8 9.4 9.2 0.5 o.o 0.5 0.2 o.8 0.5 nitralin 2 8.5 9.0 4.o 8.5 8.8 o.o o.o 1.2 o.o 1.0 1.5 alachlor 2 10~0 10.0 10.0 10.,0 9.2 1.0 o.o 0.5 1.8 3.0 0.5 alachlor 4 10.0 10.0 10.0 10.0 10.0 1.0 0.5 o.o 1.2 1.0 o.o alachlor 8 10.0 10.0 10.0 10.0 10.0 o.8 o.o o.o 2.0 3.0 0.5 chloroxuron 2 10.0 10.0 9.5 8.5 5.5 0.2 0.2 0.2 1.0 1.2 0.5 chloroxuron 8 10.0 10.0 10.0 9.8 8.2 2.0 o.o o.8 o.8 o.8 0.2 NIA 20439 2 10.0 10.0 1.0 1.8 o.o 0.2 o.o 0.5 o.o o.o 0.5 NIA 20439 4 10.0 10.0 1.5 2.2 o.8 1.0 1.0 o.8 0.2 2.0 0.2 NIA 20439 8 9.9 10.0 4.2 5.5 o.o 1.2 2.0 o.8 1.0 3.0 1.0 oryzalin 2 + 2 10.0 10.0 9.8 10.0 9.5 o.8 o.o o.o 0.5 0.5 0.2 + nitrofen oryzalin 2 + 2 10.0 10.0 9.2 10.0 10.0 1.0 o.o 0.5 2.2 5.8 3.2 + pronamide control-weeded o.o o.o 0.2 o.o o.8 0.5 o.o 1.0 0.2 o.o 1.2 control-nonweeded o.o o.o o.o o.o 1.2 0.2 o.o 4.5 o.o o.o 7.0

y phytotoxicity evaluations: 0 = no effect; 10 = dead plants

-...:i 8. Tolerance of several ornamental ground cover plant species and weed control from preemergence treatments of herbicides and herbicide combinations. Elmore, c. L., w. A. Humphrey,, A. H. Lange, and K. E. Mueller. Plants growing in competition with cultivated plants are usually considered weeds. These plants have various deleterious effects on the planted species such as increased labor costs for hand weeding, reduced plant growth (lack of nutrients, water, etc.) or are generally unsightly. Except in a few areas the principal weeds are annuals, wild oats, burclover, pigweed, etc. Some very difficult problems arise when plants like bermudagrass, field bindweed or nutsedge (nutgrass) are present.

In many ground cover plantings the herbicides trifluralin, diphenamid, DCPA, amitrole, ammonium sulfate, and others may be used. These tests were designed to obtain more information on new herbicides, some of which will soon be available for use by the public. Since most herbicides do not control various weed species, some combinations were included to get broader spectrum weed control.

Dichondra repens - All herbicides and rates were injurious to direct seeded dichondra except R 7465 at either 4 or 8 lb/A when applied as a pre­ emergence treatment.

Poa pratensis - DCPA at 8 lb/A injured Kentucky bluegrass slightly when applied as a preemergence treatment when the grass was seeded at approximately 0.5 inch in depth. All other herbicides controlled Kentucky bluegrass under these conditions in this study. Carpobrotus edule - Pronamide at 2 lb/A injured c. edule only slightly over a 222 day term whereas 4 lb/A stunted the c. edule severely. Injury with pronamide was apparent when used alone or when combined with nitrofen at 2 lb/A. There was no effect from nitrofen at 4 or 8 lb/A when evaluated from 30 to 222 days after treatment when used alone. Norea at 4 lb/A showed chlorosis at 30 to 82 days after treatment; however, no injury was observed at 172 or 222 days. At 8 lb/A norea severely injured c. edule. No other herbicide treatment or combination of herbicides showed injury.--

Delasperma alba - This iceplant is more sensitive to most herbicides than c. edule. Pronamide injured Delasperma alba at both 2 and 4 lb/A. Stunting was severe and chlorosis was observed with pronamide. Simazine at 0.25 lb/A was injurious to D. alba when applied in combinations with nitralin, trifluralin, or R 7465 on newly planted liner materials. Norea at 4 lb/A was injurious to -'D. alba showing severe chlorosis. At 8 lb/A most plants were killed. When pronaiiifci"e and nitrofen were combined at 2 lb/A each, injury from pronamide was again prevalent. The herbicides nitrofen, nitralin, DCPA, Soil Serv 463®, R 7465,. and oryzalin did not injure Q• ~ in this study. Gazania splendens - Soil Serv 463® at 8 lb/A gave severe chlorosis at 30 and 82 days after application. Regrowth was normal and by 172 days no effect was observed. At 4 lb/A chlorosis was observed only at 30 days before normal regrowth occurred. By 82 days chlorosis from simazine at 0.25 lb/A was apparent in the foliage of Gazania SP.lendens. Injury did not persist to 172 days after treatment. Norea at 4 lb7A caused chlorosis in Q.• splendens 9 and at 8 lb/A leaf burning occurred and injury was excessive. G. splendens is not a good competitor as observed by the injury from weeds-at the 172 and 222 day evaluations. The plants were weak due to shade and water competition.

Hedera canariensis - Pronamide at 4 lb/A was injurious to Hedera canariensis when applied to newly planted rooted liners. When 2 lb/A of pronamide was combined with nitrofen at 2 lb/A, stunting was slightly more severe than 2 lb/A pronamide alon~. As observed at 172 and 222 days, weed competition severely damages~· canariensis.

Osteospermum :fruticosum - Norea at 8 lb/A appeared to be the only treat­ ment to severely injure Osteospermum :fruticosum. Early herbicide symptoms were apparent with simazine and the 4 lb rate of norea; however growth was normal. Severe competition injury was apparent in the non-weeded control plots, thus Q• fruticosum must be a poor competitor.

Vinca minor - All herbicides were safe to use on Vinca minor at plant­ ing except pronamide at 2 and 4 lb/A and norea at 8 lb/A. Pronamide caused symptoms of reddening and chlorosis on the foliage as well as stunting. Norea injury appeared as veinal chlorosis. Weed competition when evaluated at 222 days had injured y. minor establishment. Sedum brevifolium - Norea at both 4 or 8 lb/A severely injured s. brevi­ folium when applied a:rter the first irrigation a:rter planting of rooted cuttings. Pronamide stunted s. brevifolium at 4 lb/A; however, 2 lb/A did not appear to injure the plantings. There appeared to be some early injury on the foliage of s. brevifolium from nitrofen at 8 lb/A. s. brevifolium is also injured from weed competition as indicated by long weak stems as found when plants grow in the shade. When pronamide at 2 lb/A and nitrofen at 2 lb/A were combined, slight injury resulted. 10

Weed ratings and weed species remaining.!/

Rate Herbicide Lb/A 11/5/70 12/22/70 5/21/71 7/28 71 pronamide 2 .o T,B,L,F .o T,M,G 3.0 E,T,P 3.5 T,E pronamide 4 9.0 T 7•5 T,M,G 3.5 E,T,M 3.2 T,E, nitrofen 4 9.2 S,L,C 9.0 C,M,L,A,S 5.5 E,P,M,C 6.5 E,T nitrofen 8 9.2 A,L,C 9.1 C,M,L,A,S 6.2 M,P,T,E 7•5 E,T,P nitralin 2 6.o F,c,P,s, 5.5 C,G,S,L, 5.8 C,T,P,S,E 5.5 E,T B R,T DCPA 8 7.2 C,L,S,A 5.8 C,M,S,L 5.5 T,P,E 5.2 E Soil Serv 463® 4 8.8 L,P,C 8. 5 C,M,L,P, 3.5 E,T,P,M 4.5 E Soil Serv 463® 8 9.5 L 9.6 L,M,S 5.0 T,M,P,E 5.8 E R 7465 4 7.5 L,S,F 8.1 o,s,c,1 6.8 D,E 6.2 E R 7465 8 8.2 S,L,F 8.8 S,L,A,L 7.0 P,S,N 8.2 E simazine + 0.25 + 2 9.5 L 9.6 C,L,M 7.5 P,T,D 8.2 E,T nitralin simazine + 0.25 + 2 9.5 L,F 9.6 C,B,L 6.8 P,C,M 7.8 E trifluralin simazine + 0.25 + 2 9.2 L,F 9.6 L,P,S 8.1 P,C,M 8.6 E,P R 7465 norea 4 8.8 P,A,L,F 9.5 L,P,G 3.8 E,M,P 5.2 E norea 8 10.0 10.0 4.5 P,M,0 5.0 P,E,T oryzalin 1 8.0 F,C,A,L, 8.5 C,L,P,B, 7.5 M,T,C 7.8 E,T G T,G,S oryzalin 2 8.8 L,F,T,S, 8.5 C,L,M,G, 7.8 M,C,G 8.1 E,T A B oryzalin 4 9.2 L 9.5 C,L 9.3 P,G, S 8.5 T R 7465 + 2 + 2 9.5 L,B 9.5 M,C,L 5.8 M,C 5.2 E nitrofen pronamide + 2 + 2 9.2 L,T 7.8 M,T,C 2. 5 E,T,P,C 3.8 T,E nitrofen control-weeded 0.5 G,S,T,C, 0.0 M,C,T,L, 0.0 E,T,M,P,V, 4.2 E,T B,L,P B,G,P,s D,C,N,G control-nonweeded - o.8 c,G,S,T, 0.0 M,C,T,L, o.o E,T,P,M,V, 2.0 E,T,P F,L,U S,B,G,P D,C,N,G

1/ weed control evaluations: 0 = no control; 10 = complete control - Convolvulus arvensis (field bindweed) not included in evaluations.

A= mustard G = common groundsel R = London rocket B = bristly oxtongue L = lupine S = shepherdspurse C = clover M = horseweed T = sowthistle E = fleabane P = pigweed U = purslane F = field bindweed 11

Tolerance of direct seeded Dichondra repens to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) after treatment. Rate Phytotoxiciti Herbicide LbLA 30 82 172 222 pronamide 2 7.2 10.0 10.0 10.0 pronamide 4 6.2 10.0 10.0 10.0 nitrofen 4 10.0 9.5 9.0 8.o nitrofen 8 9.9 10.0 9.5 9.2 nitralin 2 4.2 7.8 8.8 7.8 DCPA 8 3.5 8.9 9.9 9.8 Soil Serv 463® 4 9.9 9.8 9.2 8.8 Soil Serv 46~ 8 10.0 10.0 10.0 9.8 R 7465 4 0.5 o.o 1.0 o.8 R 7465 8 0.2 0.5 o.o 0.5 simazine + nitralin 0.25 + 2 7.0 8.5 9.0 9.0 simazine + trifluralin 0.25 + 2 9.2 9.8 9.5 9.2 simazine + R 7465 0.25 + 2 8.2 9.0 8.8 6.8 norea 4 6.5 6.5 5.2 3.0 norea 8 10.0 10.0 9.5 8.5 oryzalin 1 3.5 7.5 7.2 4.8 oryzalin 2 5.0 8.2 8.8 8.o oryzalin 4 4.8 10.0 9.8 10.0 R 7465 + nitrofen 2 + 2 8.o 6.5 5.2 3.8 pronamide + nitrofen 2 + 2 10.0 10.0 10.0 10.0 control-weeded 0.2 0.2 1.0 o.8 control-nonweeded o.o 0.2 1.2 3.2 Tolerance of Poa pratensis to several preemergence herbicides and herbi- cide combinations when evaluated at four dates (days) after treatment. Ph~otoxicitl Herbicide LbLA 30 e 172* 222* pronamide 2 10.0 10.0 pronamide 4 10.0 10.0 nitrofen 4 10.0 10.0 nitrofen 8 10.0 10.0 nitralin 2 8.2 9.2 DCPA 8 4.o 2.5 Soil Serv 463® 4 10.0 9.8 Soil Serv 463® 8 10.0 10.0 R 7465 4 10.0 10.0 R 7465 8 10.0 10.0 simazine + nitralin 0.25 + 2 10.0 10.0 simazine + trifluralin 0.25 + 2 10.0 10.0 simazine + R 7465 0.25 + 2 10.0 10.0 norea 4 10.0 10.0 norea 8 10.0 10~0 oryzalin l 8.8 8.5 oryzalin 2 7.8 9.0 oryzalin 4 8.8 9.5 R 7465 + nitrofen 2 + 2 10.0 10.0 pronamide + nitrofen 2 + 2 10.0 10~0 control-weeded o.8 1.2 control-nonweeded o.8 1.2 * not evaluated - 12

Tolerance of unrooted Carpobrotus edule to several preemergence herbi- cides and herbicide combinations when evaluated at four dates (days} after treatment. Rate Totoxicit;x: Herbicide Lb/A 30 172 222 pronamide 2 1.2 2.2 3.5 2.2 pronamide 4 1.0 3.8 5.8 5.5 nitrofen 4 0.5 o.8 0.2 o.o nitrofen 8 o.8 0.2 o.8 o.o nitralin 2 o.8 0.2 1.8 1.0 DCPA 8 o.o 0.2 1.2 1.0 Soil Serv 463® 4 1.0 0.5 1.0 o.o Soil Serv 463® 8 1.2 1.0 1.5 0.2 R 7465 4 1.0 0.5 2.0 1.5 R 7465 8 0.5 0.2 1.0 1.0 simazine + nitralin 0.25 + 2 1.2 1.2 0.5 0.5 simazine + trifluralin 0.25 + 2 0.5 o.8 0.5 o.o simazine + R 7465 0.25 + 2 o.8 1.0 0.5 0.2 norea 4 2.5 3.0 1.8 1.0 norea 8 5.2 8.o 9.2 9.2 oryzalin 1 1.8 1.0 1.5 0.5 oryzalin 2 1.0 0.2 1.0 0.2 oryzalin 4 o.o 0.5 o.8 0.2 R 7465 + nitrofen 2 + 2 1.2 0.5 2.0 0.5 pronamide + nitrofen 2 + 2 2.5 3.5 3.0 2.5 control-weeded 0.2 o.o 1.2 o.8 control-nonweeded 0.5 0.2 J•O 5.2

Tolerance of Delasperma ~ to several preemergence herbicides and herbi- cide combinations when evaluated at four dates (days} after treatment. Rate Ph~otoxicit;x: Herbicide Lb/..A 30 s- 172 222 pronamide 2 3.2 6.0 8.8 8.2 pronamide 4 4.2 6.5 8.8 9.2 nitrofen 4 1.2 1.8 1.0 0.2 nitrofen 8 2.2 1.8 1.0 o.o nitralin 2 0.5 o.8 1.0 o.8 DCPA 8 o.o 0.2 0.5 1.0 Soil Serv 46 3® 4 1.8 1.0 1.2 0.5 Soil Serv 463® 8 1.2 2.5 1.8 1.0 R 7465 4 2.0 1.2 1.0 1.2 R 7465 8 1.2 1.2 o.8 o.8 simazine + nitralin 0.25 + 2 2.5 4.2 6.o 5.5 simazine + trifluralin 0.25 + 2 3.0 4.8 5.5 5.8 simazine + R 7465 0.25 + 2 4.8 5.2 5.5 5.5 norea 4 3.5 5.8 4.8 3~5 norea 8 6.5 8.2 9.2 9.5 oryzalin 1 o.8 1.0 1.2 o.8 oryzalin 2 0.5 1.0 o.8 1.0 oryzalin 4 1.0 1.0 o.o o.o R 7465 + nitrofen 2+2 2.5 0.2 0.5 o.8 pronamide + nitrofen 2 + 2 5.2 7.0 8.2 7.8 control-weeded o.8 0.2 1.2 1.0 control-nonweeded 1.2 o.o 3.0 3.2 13

Tolerance of Gazania splendens to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) after treatment. Rate Phytotoxiciti Herbicide LbLA JO 82 172 222 pronamide 2 o.o 0.5 2.0 1.5 pronamide 4 2.2 1.2 1.5 1.2 nitrofen 4 1.0 1.8 1.0 o.o nitrofen 8 1.5 1.8 0.2 0.5 riitralin 2 o.8 1.8 1.2 1.0 DCPA 8 1.0 1.2 2.0 2.2 Soil Serv 463® 4 3.0 1.0 1.0 0.5 Soil Serv 46 3® 8 4.5 4.5 0.2 o.o R 7465 4 1.5 1.5 1.5 2.0 R 7465 8 1.2 1.8 2.0 0.5 simazine + nitralin 0.25 + 2 2.0 3.5 2.0 1.2 simazine + trifluralin 0.25 + 2 2.2 3.0 1.0 o.o simazine + R 7465 0.25 + 2 2.8 4.8 2.8 1.8 norea 4 1.2 3.0 1.2 0.2 norea 8 2.8 4.8 2.8 1.8 oryzalin 1 1.0 1.2 0.5 o.o oryzalin 2 1.0 1.0 2.0 0.5 oryzalin 4 1.0 1.0 1.8 0.5 R 7465 + nitrofen 2 + 2 2.0 1.8 0.2 0.5 pronamide + nitrofen 2 + 2 1.8 1.5 1.5 o.8 control-weeded 0.5 1.0 o.8 o.o control-nonweeded ' o.~ 1.0 4.2 4.o Tolerance of Hedera canariensis to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) after treatment.

R(:l.te ~otoxiciti Herbicide LbLA 30 2 172 222 pronamide 2 1.5 o.o 2.2 2.0 pronamide 4 4.o 3.0 6.o 4.2 nitrofen 4 2.5 2.2 1.2 0.5 nitrofen 8 1.0 1.5 o.o o.o nitralin 2 o.8 2.0 2.2 1.5 DCPA 8 0.5 0.5 o.8 1.0 Soil Serv 46'{iJ 4 1.2 o.8 o.o o.o Soil Serv lf63® 8 2.0 1.2 o.o o.o R 7465 4 0.5 o.8 o.o o.o R 7465 8 1.2 2.2 o.8 1.0 simazine + nitralin 0.25 + 2 o.8 1.2 0.2 o.o simazine + trifluralin 0.25 + 2 o.o o.8 o.o o.o simazine + R 7465 0.25 + 2 0.5 2.2 o.o o.o norea 4 1.5 3~2 0.2 o.8 norea 8 2.2 3.8 0.2 o.o oryzalin l 1.8 2.2 1.0 o.8 oryz_alin 2 o.8 1.5 o.o o.o oryzalin 4 1.0 0.2 o.o o.o R 7465 + nitrofen 2 + 2 1.8 o.o o.o 0.2 pronamide + nitrofen 2 + 2 2.2 1.8 1.5 2.2 control-weeded 1.2 1.2 0.5 0.5 control-nonweeded o.8 0.5 3.0 6.o 14

Tolerance of 0steospermum fruticosum to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) a:f'ter treatment. Rate ~otoxicitl Herbicide LbLA 30 112 222 pronamide 2 0.2 o.o 0.5 1.0 pronamide 4 1.2 o.8 1.5 1.8 nitrofen 4 o.8 1.8 o.o 0.2 nitrofen 8 1.2 o.8 o.o o.o nitralin 2 0.5 0.5 1.0 1.0 DCPA 8 1.0 o.o 0.2 0.5 Soil Serv 463® 4 0.5 0.5 o.o o.8 Soil Serv 463® 8 1.2 1.0 0.5 1.0 R 7465 4 0.2 o.o 0.5 1.5 R 7465 8 1.2 1.5 o.8 0.2 simazine + nitralin 0.25 + 2 2.5 2.2 1.0 1.2 simazine + trifluralin 0.25 + 2 1.0 1.8 0.2 o.8 simazine + R 7465 0.25 + 2 2.2 2.8 0.5 1.0 norea 4 2.0 2.2 o.o o.o norea 8 3.5 4.8 3.0 3.8 oryzalin 1 1.2 0.5 o.o o.o oryzalin 2 1.5 0.5 0.5 o.8 oryzalin 4 1.2 1.0 o.o 1.2 R 7465 + nitrofen 2 + 2 1.5 o.8 o.o 0.5 pronamide + nitrofen 2 + 2 1.8 o.8 0.2 o.8 control-weeded 0.2 o.o o.o 0.2 control-nonweeded 0.5 o.o 4.2 :z:. 5 Tolerance of Vinca minor to several preemergence herbicides and herbi- cide combinations when evaluated at four dates (days) a:f'ter treatment. Rate ~otoxicitl Herbicide LbLA 30 2 172 222 pronamide · 2 2.2 3.5 6.0 5.2 pronamide 4 3.8 5.0 7.8 8.8 nitrofen 4 1.5 0.5 0.5 o.8 nitrofen 8 1.2 o.o 0.2 0.2 nitralin 2 0.5 o.o 0.5 2.0 DCPA 8 o.8 1.2 o.8 1~2 Soil Serv 463® 4 0.2 o.8 o.o 1.2 Soil Serv 463® 8 1.2 1.5 o.o 0.2 R 7465 4 0.2 o.8 o.o 1.2 R 7465 8 0.5 0.2 0.5 1~8 simazine + nitralin 0.25 + 2 o.8 0.5 o.o o.8 simazine + trifluralin 0.25 + 2 1.2 0.2 o.o o~o simazine + R 7465 0.25 + 2 o.8 0.5 0.2 1.0 norea 4 1.0 2.2 o.o o.o norea 8 5.0 5.8 4.o 4.2 oryzalin 1 1.2 o.8 o.o o.8 oryzalin 2 0~5 0.2 0.5 1.2 oryzalin 4 o.8 0.5 1.2 1.8 R 7465 + nitrofen 2 + 2 1.8 1.0 0.5 1.2 pronamide + nitrofen 2 + 2 3.2 .1.8 4.2 5.2 control-weeded 0.2 0.2 o.8 1.8 control"nonweeded - o.o 0.5 1.2 3.0 15

Tolerance of Sedum brevifolium to several preemergence herbicides and herbicide com'6ina"tions when evaluated at four dates (days) after treatment.

Rate Phytotoxiciti Herbicide Lb[A 30 82 112 222 pronamide 2 0.5 o.o 1.8 1.2 pronamide 4 1.8 2.0 4.o 4.2 nitrofen 4 2.0 1.5 1.5 1.2 nitrofen 8 3.8 3.8 2.5 1.5 nitralin 2 0.5 o.o 2.2 1.8 DCPA 8 1.5 1.2 1.2 0.2 Soil Serv 463® 4 0.2 o.o 0.5 Soil Se rv 46 3® 8 0.5 0.2 0.5 o.o R 7465 4 o.8 0.5 2.0 2.0 R 7465 8 1.0 0.5 2.2 1.2 simazine + nitralin 0.25 + 2 o.8 0.5 1.2 o.8 simazine + trifluralin 0.25 + 2 1.0 0.2 0.5 o.o simazine + R 7465 0.25 + 2 0.5 o.o 0.5 0.2 norea 4 5.0 5.8 4.2 4.8 norea 8 8.5 8.8 9.0 9.8 oryzalin l 1.8 0.2 1.2 0.2 oryzalin 2 0.2 o.o o.8 0.5 oryzalin 4 1.8 1.8 2.0 2.5 R 7465 + nitrofen 2 + 2 2.5 1.0 1.8 1.0 pronamide + nitrofen 2 + 2 3.5 2.5 3.0 2.8 control-weeded o.o o.o 1.0 o.8 control-nonweeded o.8 o.o 1.8 3.8 16

Tolerance of several ornamental ground cover plant species and weed control from preemergence treatments of herbicides and herbicide combinations. Elmore, c. L., E. Roncoroni, L. Smith and w. Mast. Several herbicides were studied on eleven ground cover species at Davis, California. The Yolo clay loam soil (o.M. 4-3%, sand 25.2%, silt 60%, and clay 14.8%) was preirrigated and prepared for planting by rototilling. Ten ground cover species were planted May 18, 1970, as rooted liners in 2 inch plant bands. The Carpobrotus edule was planted as unrooted cuttings. The plants were irrigated well for 3 days; however, the soil surface was dry when the herbicides were applied with a knapsack sprayer in 100 gallons of water on May 22, 1970. A sprinkler irrigation followed the application. The herbicides were applied to 10 1 x 20' plots and were replicated 4 times. Evaluations of weed control and phytotoxicity to the ground cover species were taken periodically throughout the season. After 2 months, on July 20, 1970, the plots were individually hand weeded and a comparison of the costs for the various herbicides was detennined. A time was taken to weed each plot and was converted to cost in dollars per acre with a labor charge of $2.00 per hour. The weed species present in the January 13, 1971, evaluation were connnon groundsel, annual bluegrass, common chickweed, and co:rm:non mustard. The effects of various herbicides are discussed by ground cover specie. Tolerance of unrooted Carpobrotus edule to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) after treatment.

Phytotoxicity Herbicide Lb/A 25 70 101 326 pronamide 2 o.o 2.8 2.2 1.0 pronamide 8 0.5 5.5 5.8 6.5 nitrofen 4 o.o 1.8 1.0 0.5 nitrofen 8 o.o 2.3 2.0 1.2 nitralin 2 o.o 1.5 1.5 2.2 DCPA 8 o.o 2.0 1.0 0.5 Soil Serv 463® 6 o.o 1.5 o.8 o.8 Soil Serv 463® 12 o.o 1.5 1.8 1.2 R 7465 4 o.8 2.0 1.8 2.5 R 7465 8 o.o 3.0 2.2 4.o simazine + nitralin 0.5 + 4 o.o 2.3 1.2 0.5 GS 13638 2 0.2 1.5 1.8 1.8 GS 13638 8 3.8 4.3 3.0 4.o simazine + R 7465 0.5 + 2 o.o 2.5 1.2 2.0 simazine + trifluralin 0.5 + 2 0.2 2.8 2.0 4.5 control o.o 1.5 1.5 2.5 17

Tolerance of Hedera canariensis to several preemergence herbicides and herbicide combinations when evaluated at four dates(days) after treatment.

Rate Pbytdtoxic:lty Herbicide LbLA 25 70 101 32b pronamide 2 1.0 4.8 4.o 3.8 pronamide 8 o.o 2.8 4.2 4.2 nitrofen 4 0.2 2.5 2.2 o.o nitrofen 8 1.0 2.0 2.0 0.5 nitralin 2 1.2 2.0 2.0 0.5 DCPA 8 1.5 1.8 1.2 0.2 Soil Serv li6'3® 6 o.8 2.0 1.8 1.2 Soil Serv !J63® 12 0.5 2.8 3.8 1.0 R 71J65 4 2.0 2.3 2.2 0.2 R 71J65 8 1.0 2.5 2.8 1.2 simazine + nitralin 0.5 + 4 0.2 1.8 1.8 o.8 GS 13638 2 o.8 3.3 1.5 3.8 GS 13638 8 o.8 3.3 2.0 1.0 simazine + R 7li65 0.5 + 2 1.2 3.0 2.0 1.5 simazine + trifluralin 0.5 + 2 o.o 2.0 1.5 0.2 Control o.o 2.3 2.0 2.0

Tolerance of Delasperma ill!, to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) after treatment.

Rate Ph~otoxicitl Herbicide Lb/A 25 70 101 32b pronamide 2 2.0 7.3 8.2 8.o pronamide 8 o.8 6.o 6.8 8.o nitrofen 4 2.5 4.3 3.0 3.0 nitrofen 8 o.8 o.8 0.5 0.5 nitralin 2 0.2 1.0 0.5 1.2 DCPA 8 o.o 1.5 o.8 1.0 Soil Serv !J63® 6 o.8 2.0 1.8 2.8 Soil Serv !J63® 12 1.8 1.0 o.8 2.0 R 71J65 4 1.0 1.5 2.2 3.0 R 71J65 8 o.8 2.3 1.2 4.8 simazine + nitralin 0~5 + 4 6.o, 9.3 8.5 6.8 GS 13638 2 4.2 3.5 3.8 2.8 GS 13638 8 8.5 9.3 7.8 8.8 siroazine + R 7li65 0.5 + 2 3.8 9.3 9.2 8.5 simazine + trifluralin 0.5 + 2 6.8 8.6 8.2 8.o Control o.o 2.0 2.0 2.2 18

Tolerance of Malephora luteolus to several preemergence herbicides and herbicide combinations when evaluated at four dates(days) af'ter treatment.

Rate Phytotoxicitr Herbicide Lb/A 25 70 101 326 pronamide 2 1.5 5.9 5.8 5.0 pronamide 8 1.8 8.9 9.2 9.2 nitrofen 4 1.5 3.5 3.5 2.8 nitrofen 8 o.o 1.0 0.5 0.5 nitralin 2 o.8 2.5 1.8 2.2 DCPA 8 0.5 1.5 o.8 o.o Soil Serv 463® 6 3.0 3.5 4.o 3.8 Soil Serv 463® 12 6.5 5.8 5.2 2.2 R 7465 4 2.2 2.8 2.0 3.8 R 7465 8 3.5 6.o 5.0 7.0 simazine + nitralin 0.5 + 4 9.2 10.0 10.0 10.0 GS 13638 2 7.8 7.8 7.8 7.5 GS 13638 8 8.5 9.0 8.8 8.5 simazine + R 7465 0.5 + 2 8.o 8.3 8.8 8.2 simazine + trifluralin 0.5 + 2 9.5 9.3 9.8 10.0 Control o.o 3.3 2.8 3.0

Tolerance of Dichondra repens to several preemergence herbicides and herbicide combinations when evaluated at four dates(days) a:rter treatment.

Rate Pb_ytotoxicity Herbicide Lb/A ~5 70 101 326 pronamide 2 10.0 9.8 pronamide 8 10.0 10.0 nitrofen 4 10.0 8~0 nitrofen 8 10.0 10.0 nitralin 2 10.0 10.0 DCPA 8 10.0 9.7 Soil Serv 463® 6 10.0 9.2 Soil Serv 463® 12 10.0 10.0 R 7465 4 3.3 o.8 R 7465 8 5~0 1.2 simazine + nitralin 0.5 + 4 10.0 10.0 GS 13638 2 10.0 9.5 GS 13638 8 10.0 10.0 simazine + R 7465 0.5 + 2 10.0 10.0 simazine + trifluralin 0.5 + 2 10.0 10~0 Control 2.5 2.8 19

Tolerance of Poa pratensis to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) af'ter treatment.

Rate Phytotoxicity Herbicide Lb/A 25 70 101 326 pronamide 2 10.0 10.0 pronamide 8 10.0 10.0 nitrofen 4 10.0 10.0 nitrofen 8 10.0 10.0 nitralin 2 10.0 9.0 DCPA 8 8.o 5.5 Soil Serv 46'3® 6 9.2 8.8 Soil Serv 463® 12 7.8 8.5 R 7465 4 10.0 10.0 R 7465 8 10.0 10.0 simazine + nitralin 0.5 + 4 10.0 10.0 GS 13638 2 10.0 9.5 GS 13638 8 10.0 10.0 simazine + R 7465 0.5 + 2 10.0 10.0 simazine + trifluralin 0.5 + 2 10.0 10.0 Control 5.5 2.5

Tolerance of 0steospermum fruticosum to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) after treatment. Rate Phytotoxicity Herbicide Lb/A ~5 70 101 326 pronamide 2 0.2 3.3 2.5 2.0 pronamide 8 o.o 1.3 1.0 0.2 nitrofen 4 o.o 1.5 1.0 o.8 nitrofen 8 o.o 1.5 1.2 0.5 nitralin 2 o.o 1.8 1.8 0.2 DCPA 8 o.o 1.8 1.8 o.8 Soil Serv 463® 6 2.7 2.5 2.0 2.0 Soil Serv 46'3® 12 4.o 3.8 2.8 2.2 R 7465 4 o.o 1.8 1.8 0.5 R 7465 8 o.o 1.8 1.8 2.0 simazine + nitralin 0.5 + 4 8.5 9.5 8.2 9.8 GS 13638 2 1.5 3.5 4.o 2.5 GS 13638 8 8.2 7.8 6.5 7.2 simazine + R 7465 0.5 + 2 6.2 8.6 8.8 8.2 simazine + trifluralin 0.5 + 2 9.0 9.5 9.8 10.0 Control o.o 2.3 2.2 o.8 20

Tolerance of Gazania splendens to several preemergence herbicides and herbicide combinations when evaluated at four dates· .(days)· a:f'ter treatment.

Rate Phytotoxici~ Herbicide Lb/A 25 70 101 326 pronamide 2 1.5 7.0 6.o 7.0 pronamide 8 o.8 2.0 0.3 1.0 nitrofen 4 0.5 2.7 1.3 1.7 nitrofen 8 o.o 2.3 1.0 o.o nitralin 2 o.o 2.3 0.7 1.0 DCPA 8 o.o 1.7 1.0 0.7 Soil Serv 46'3® 6 1.8 3.7 2.0 1.3 Soil Serv 463® 12 2.2 4.7 2.7 3.3 R 7465 4 0.2 1.7 1.3 0.7 R 7465 8 o.8 3.7 2.7 3.0 simazine + nitralin 0.5 + 4 4.5 8.7 6.7 7.0 GS 13638 2 3.5 6.7 4.3 6.3 GS 13638 8 7.0 10.0 10.0 10.0 simazine + R 7465 0.5 + 2 3.2 7.3 7.7 6.3 simazine + trifluralin 0.5 + 2 4.8 9.3 9.3 9.7 Control o.o 3.0 1.7 1.3

Tolerance of Hedera helix to several preemergence herbicides and herbicide combinations when evaluated at four dates (days)a:f'ter treatment. Rate ;RhY:totoxicity Herbicide Lb/A 25 70 101 326 pronamide 2 o.8 3.8 3.8 1.0 pronamide 8 0.2 2.8 3.5 5.0 nitrofen 4 0.2 2.8 1.8 0.5 nitrofen 8 o.o 1.3 2.0 o.o nitralin 2 0.2 1.5 1.5 0.5 DCPA 8 0.2 1.5 1.8 0.5 Soil Serv 46'3® 6 0.5 2.0 1.5 o.o Soil Serv 463® 12 1.2 3.8 2.2 o.o R 7465 4 o.o 1.5 1.8 0~5 R 7465 8 o.o 2.5 2.5 2.0 simazine + nitralin 0.5 + 4 o.8 1.0 1.5 o.o GS 13638 2 1.2 2.8 2.5 0.5 GS 13638 8 0.5 2.8 2.8 0.5 simazine + R 7465 0.5 + 2 o.o 1.8 2.2 o.o simazine + trifluralin 0.5 + 2 0.2 2.0 1.0 1.0 Control o.o 1.8 1.8 1.0 21

Tolerance of Ajuga repens to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) af'ter treatment.

Rate Pbytotoxicity Herbicide Lb/A 25 70 101 326 pronamide 2 2.4 6.7 6.7 6.3 pronamide 8 1.9 9.8 10.0 10.0 nitrofen 4 2.7 3.0 2.0 3.3 nitrofen 8 4.4 2.0 0.7 1.7 nitralin 2 0.7 6.7 7.7 8.o DCPA 8 0.7 0.5 0.5 o.8 Soil Serv 463® 6 1.7 0.5 o.8 1.0 Soil Serv 46 '3® 12 6.o 4.o 2.3 4.o R 7465 4 o.o 1.0 1.0 0.2 R 7465 8 0.3 0.7 0.3 0.2 simazine + nitralin 0.5 + 4 7.9 10.0 9.7 9.8 GS 13638 2 7.7 7.3 6.5 8.8 GS 13638 8 10.0 10.0 10.0 10.0 simazine + R 7465 0.5 + 2 7.7 7.5 6.5 6.8 simazine + trifluralin 0.5 + 2 8.9 9.7 9.3 9.8 Control o.o 1.3 0.7 o.8

Tolerance of Sedum brevifolium to several preemergence herbicides and herbicide combinations when evaluated at four dates (days) after- treatment.

Rate Phytotoxicity Herbicide Lb/A 25 70 101 326 pronamide 2 o.o 2.0 2.0 2.0 pronamide 8 o.8 2.3 1.8 1.8 nitrofen 4 o.o 1.5 1.8 1.2 nitrofen 8 o.o o.8 o.8 0.5 nitralin 2 1.0 1.8 2.0 3.0 DCPA 8 0.2 2.8 1.2 1.5 Soil Serv 463® 6 0.5 1.5 1.0 3.8 Soil Serv 46'3® 12 1.5 2.3 2.0 1.8 R 7465 4 2.2 3.5 2.8 4.o R 7465 8 2.0 3.5 2.3 6.8 simazine + nitralin 0.5 + 4 o.o 2.8 2.5 3.0 GS 13638 2 3.8 5.3 4.8 6.o GS 13638 8 9.0 9.3 9.7 9.5 simazine + R 7465 0.5 + 2 o.o 2.0 2.0 2.5 simazine + trifluralin 0.5 + 2 1.2 1.8 2.2 2.8 Control o.o 4.o 4.o 3.8 22

Tolerance of Vinca minor to several preemergence herbicides and herbi- cide combinations when evaluated at four dates (days) a"f'ter treatment.

Rate Phytotoxicit;2: Herbicide Lb/A 25 70 101 326 pronamide 2 o.o 3.3 5.5 3.8 pronamide 8 o.8 6.o 7.2 9.0 nitrofen 4 o.o 3.0 2.2 o.8 nitrofen 8 o.o 2.5 1.5 0.5 nitralin 2 o.o 2.8 2.0 4.5 DCPA 8 0.5 3.3 3.5 5.2 Soil Serv 463® 6 1.5 1.8 0.7 1.8 Soil Serv 463® 12 3.2 2.5 1.8 2.5 R 7465 4 o.o 2.0 2.5 0.5 R 7465 8 0.2 3.0 2.2 1.2 simazine + nitralin 0.5 + 4 0.2 3.5 3.0 2.5 GS 13638 2 0.2 2.8 2.8 2.5 GS 13638 8 6.8 7.6 5.8 8.o simazine + R 7465 0.5 + 2 1.2 2.8 2.2 2.0 simazine + trifluralin 0.5 + 2 1.0 3.8 3.2 3.2 Control o.o 1.3 1.5 2.2

Tolerance of :gypericum cal;2:cinum to several preemergence herbicides and herbicide combinations when evaluated at four dates (days)· after treatment.

Rate Phytotoxicit;2: Herbicide Lb/A 25 70 101 326 pronamide 2 0.5 5.0 5.5 5.2 pronamide 8 1.5 5.5 7.5 7.5 nitrofen 4 1.5 5.3 5.0 3.0 nitrofen 8 0.2 3.5 3.5 2.2 nitralin 2 0.2 3.0 1.5 1~5 DCPA 8 o.o 3.0 2.2 1.5 Soil Serv 46'§EJ 6 1.2 3.5 3.0 3.8 Soil Serv 463® 12 o.o 2.3 2.0 o.8 R 7465 4 o.8 6.o 6.2 6.o R 7465 8 o.o 2.5 3.5 1.5 simazine + nitralin 0.5 + 4 3.0 5.9 5.5 6.2 GS 13638 2 2.2 3.3 2.8 1.8 GS 13638 8 1.2 4.8 2.8 3.5 simazine + R 7465 0.5 + 2 1.5 4.o 4.o 2.5 simazine + trifluralin 0.5 + 2 1.5 5.5 5.0 4.o Control o.o 4.8 4.8 2.5 23

Ca obrotus edule - Pronamide gave slight injury to Carpobrotus edule at 2 lb A; however, 8 lb/A severely injured c. edule. Nitrofen at 4 and 8 lb/A, nitralin at 2 lb/A, DCPA at 8 lb/A, and Soil Serv li63® at 6 and 12 lb/A did not appear to injure Q• edule. The herbicides R 7li65 at 8 lb/A, GS 13638 at 8 lb/A, and simazine plus trifluralin at 0.5 plus 2 lb/A also injured£• edule. Lower rates of R 7li65 and GS 13638 did not injure c. edule. A combination 0£ simazine plus nitralin or R 7~5 did not injure c. edule at the rates used in this study.

Delasperma alba - The herbicides nitralin at 2 lb/A, DCPA at 8 lb/A, Soil Serv ii>3® atband 12 lb/A, and R-7li65 and nitrofen at 4 lb/A did not injure Delasperma alba. Pronamide at 2 and 8 lb/A and those treatments containing simazine severely injured D. alba. The herbicides GS 13638 and R 7~5 at 8 lb/A also injured D. alba7 ~injury with R 7li65 appeared as stunting and became progressively more severe.

Hedera canariensis - All treatments except pronamide at both 2 and 8 lb/A appeared to allow satisfactory establishment of H. canariensis. Pronamide severely stunted H. canariensis. The herbicide GS 13638 at 8 lb/A and Soil Serv li63® caused temporary chlorosis; however, regrowth was normal. Malephora luteolus - Several herbicide treatments injured Malephora luteolus. Nitrofen at 4 and 8 lb1/A, nitralin at 2 lb/A, DCPA at 8 lb/A, and R 7465 at 4 lb/A appeared to have adequate safety on newly planted rooted M. luteolus. Most treatments gave severe chlorosis (yellowing} or killing of the plants. Simazine in combination with nitralin, R 7465, or trifluralin was killing plants even at 0.5 lb/A of simazine. 0steospermum. fruticosum (African trailing daisy} - In this test all combinations of herbicides containing simazine at 0.5 lb/A severely injured newly planted rooted 0steospermum fruticosum. Chlorosis was apparent with GS 13638 at 2 lb/A and injury was severe at 8 lb/A. Early chlorosis was also observed with 6 and 12 lblA of Soil Serv 463®; however the plants grew out of these symptoms. All other herbicides did not give significant injury. Gazania splendens - The herbicide combinations containing simazine at 0.5 lb1/A and GS 13638 at 2 or 8 lb/A severely injured Gazania splendens. Soil Serv li63® also caused slight injury at 12 lb/A during the entire test. other herbicides, nitrofen, nitralin, DCPA, and R 7465 did not appear to appreciably affect Q• splendens establishment.

Hedera helix (English ivY) - All herbicides except pronamide at 8 lb/A allowed excellent establishment of Hedera helix without appreciable injury.

~ repens (carpet bugle} - In this test DCPA at 8 lb/A, Soil Serv 463® at 6 lbTA; and R 7465 at 4 or 8 lb/A all showed safety to Ajuga repens. Soil Serv 463® at 12 lb/A and nitrofen at 4 and 8 lb/A gave somewhat less selectivity but _much more than the remaining herbicides and combinations used in the test. Sedum brevifolium - The herbicides GS 13638 at 2 and 8 lb/A and R 7465 at 8 lb1/A was not selective on Sedum brevifolium. other herbicides including simazine at 0.5 lb/A in combination with nitralin, R 7465 or trifluralin allowed the plants to establish normally. 24

Vinca minor (periwinkle) - Most herbicides were safe to use in Vinca minor in this test. Pronamide at 2 or 8 lb/A and GS 13638 at 8 lb/A were injurious to v. mino~. DCPA also appeared to reduce the growth in this test; however-this has not been true in other tests. Simazine at 0.5 lb/A gave the characteristic interveinal yellowing; however it did not appear to affect growth or establishment.

Hypericum calycinum - A poor Hy-pericum calycinum stand was established in most plots including some of the untreated plots. It was apparent, how­ ever, that nitralin and DCPA would be safe to use on~- calycinum. Probably nitrofen, Soil Serv 46'3®, GS 13638 at 2 lb/A and possibly other herbicides could also be used on_B:. calycinum. Further testing is necessary to eval­ uate herbicides on this plant. Dichondra re ens (dichondra) - All herbicides except R 7465 at 4 and possibly at 8 lb A were too injurious to dichondra when applied as a post­ plant, preemergence application. Bluegrass mixture - Almost all treatments gave 100 percent control of this mixture when applied postplant preemergence. DCPA at 8 lb/A appeared to have some selectivity when the seed was planted about 0.5 inch in depth. Weed Control Good control was achieved with all herbicides in this test at 1 month after application. After 2 months, however, nitrofen at 8 lb/A, DCPA at 8 lb/A, R 7465 at 8 lb/A, GS 13638 at 8 lb/A, and simazine at 0.5 lb/A plus nitralin or trifiuralin at 2 lb/A were the only treatments giving approxi­ mately 70 percent control or better. Prostrate pigweed and groundsel were the principal weeds in most plots. After handweeding at 2 months the control was better with all treatments; however, there was still a heavy stand of prostrate pigweed in the R 7465 treatments. When the weed con~rol was eval­ uated the following January (215 days), R 7465 at 4 or 8 lb/A was giving excellent control of annual bluegrass and common chickweed. All herbicide treatment appreciably reduced the cost of weeding at 2 months. Because of the weed pressure all treatments needed weeding, however if a herbicide controlled prostrate pigweed or groundsel costs were relatively low. Nitrofen at 8 lb/A had the lowest cost at $150 per acre and it was one of the safer materials on all species. Although the treatments con­ taining simazine reduced weeding costs drastically several species were injured. DCPA at 8 lb/A also was a safe treatment that reduced costs drastically. Weed control and cost evaluations of several herbicides and herbicide combinations on newly planted ground covers

Rate Weed Control and Wee

p = prostrate pigweed u = purslane g = common groundsel 1 = lambsquarters b = barnyardgrass c = crabgrass k = knotweed e = spotted spurge s = sowthistle m = burclover

I\) \Jl 26 Tolerance of several established ground cover species to five post­ emergence herbicides. Elmore, c., D. Hamilton, E. Johnson, and T. Kretchun. Few herbicides can be used safely as a postemergence treatment over a broad spectrum of ground cover species. If weeds escape preemergence treatment or are not treated, they normally must be removed mechanically or by hand before a preemergence herbicide treatment is then applied.

Five herbicides were applied as broadcast sprays over established rows of nine ground cover species at the San Jose Field Station. Treatments were applied July 26, 1971, using a Champion knapsack sprayer with three Teejet 8004 nozzles at a pressure of approximately 30 psi. No surfactants were used with any treatment. Each treatment was replicated four times. Injury evalu­ ations (Tables 1 and 2) were made September 1, 1971, September 30, 1971, and October 22, 1971. Vinca minor - Vinca minor was initially injured severely with bromoxynil by complete removal of leaves at a rate of 1 lb/A. Regrowth was unaffected, however. Also amitrole and 2,4-D amine gave their characteristic symptoms early with only amitrole persisting more than a month. MCPP appeared to be much safer than 2,4-D amine on v. minor. Linuron did not injure v. minor at 1 or 2 lb/A. -

Hypericum calycinum - Initially injury was evident from amitrole shown by chlorotic symptoms, 2,4-D amine, and bromoxynil. Bromoxynil at 1 lb/A burned foliage; however, recovery was complete. Amitrole symptoms remained 7 weeks after application. Delasperma alba - Almost all herbicide treatments injured Delasperma alba. Amitrole severely yellowed the plants with symptoms lasting over 7 weeks. 2,4-D amine and MCPP injury appeared as twisting of new growth and tip die back. Linuron reddened leaves and stunted the D. alba at both 1 and 2 lb/A; however, 1 lb/A would appear to be safe enough.- -- Gazania splendens - Although there was a marginal stand for evaluating Gazania splendens, it was apparent that linuron, MCPP, or bromoxynil did not excessively injure the plants. Amitrole discolored foliage; however, it did not kill the plants at 1 lb/A. 2,4-D amine at 0.5 lb/A did not appear to injure Q.• splendens. Hedera helix - Amitrole at 1 lb/A was the only treatment which appeared to affect Hedera helix. These symptoms were the normal amitrole chlorosis. No injury was apparent from the other herbicides. Carpobrotus edule - Several interesting effects were noted with herbicides on Carpobrotus edule. Linuron caused a severe red spotted condition on the foliage which was apparently due to spray droplets. Amitrole gave only slight chlorosis at 1 lb/A in this test. MCPP at l lb/A appeared to give only slight distortion of growth; however 2 lb/A was more severe and unacceptable. Injury was also unacceptable with 2,4-D amine at 0.5 lb/A for the first month after treatment. Regrowth, however, occurred and symptoms were reduced. Bromoxynil severely injured Q• edule (Table 2) as observed by foliag~ necrosis. 27

Sedum brevifolium - All herbicides and rates appeared to be acceptable on Sedumbrevifolium. Bromoxynil at 1 lb/A did kill the flower stalks which werepresent at treatment.

AJuga repens - The herbicide bromoxynil at 1 lb/A did not injure Ajuga repens. MCPP and amitrole severely injured A. repens giving characteristic symptoms of distortion and chlorosis respectively. A:rter 7 weeks, however, only slight leaf discoloration and stunting were observed.

Sunnnary Generally linuron did not severely injure any of the ground cover species at these rates except c. edule. Amitrole at 1 lb/A could be applied to all species except A. repens or-D. alba without severe injury. Injury from MCPP was less severe In most instances than 2,4-D and would appear to be safer in these /:,· tests at herbicidal rates. Injury was apparent from MCPP on A. repens, •' whereas, 2,4-D amine did not appear to give injury in this test. Bromoxynil I ' appeared to give a contact affect only as indicated by early burning on c. edule, Q• ~, !!• cal~cinum, and y. minor; however, regrowth was normal7 28

Annual weed control in nine ground covers with ten herbicides - u.c. Deciduous Fruit Station, San Jose, 1970-71. Hamilton, w. Douglas, Clyde L. Elmore, Edward J. Johnson. The object of this work was to find safe, effective, reliable and economical chemical controls of annual weeds in nine of the most used and widely planted, low-growing ornamentals. The trial had three parts and two sub-parts. 1. Plant ground covers May 15, 1970, irrigate, treat on Ma.y 18, and irrigate (assess control of summer weeds). Obtain the cost of hand weeding all plots 2 months later (needed at that time). 2. Retreat plots with the same materials October 27, 1970 ( assess control of winter weeds). Obtain the cost of hand weeding all plots 8 months later. 3. Test the tolerance of the same plants to five postemergence herbicides. Materials broadcast over the plants on July 26, 1971. Results of this test are compiled separately.

Results - Weed Control

Excellent weed control was obtained from most herbicides 1 to 2 months after the May application and up to the end of October when hand weeded once in July as required by some treatments. Weed control from the October treat­ ments was satisfactory for a longer time without hand weeding (hand weeded 2 months after spring application, 8 months after fall application).

The average cost at $9.50/hr per 1000 square feet for hand weeding plots in the spring was: chemically treated $3.45, non-treated $20.40, range $.80 to $11.40 {all except 2 were under ~.00). The average hand weeding cost 8 months after the fall treatment was lower: chemically treated $1.93, non­ treated $4.73, range $.70 to $5.60.

Results - Phytotoxicity Carpobrotus edule - The 8 lb/A rate of pronamide and R 7465 stunted growth while lower rates°appeared safe in the May treatment. GS 13638 at 8 lb/A caused slight chlorosis. Branch rooting 4 months after the May treatments was variable. Differences in care at time of planting and soil moisture variations appeared to be important causes of the differences in rooting. Stunting and discoloration was observed from the October retreatment with pronamide at 2 lb/A and was severe at 8 lb/A. Plants treated with 8 lb/A of R 7465 were stunted from the second application of 8 lb/A.

Ajuga repens - Growth was stunted by pronamide at 8 lb/A, GS 13638 at 8 lb/A, nitrofen at 8 lb/A, and treatments containing simazine, the effects from the second treatment persisting into the winter. They later recovered. Delasperma alba - This plant is quite sensitive to herbicides and was severely burned by GS 13638 at 8 lb/A and was severely stunted by pronamide at 2 and 8 lb/A. The foliage became chlorotic a month after the May treatments and 3 months after the October treatments containing simazine. No phytotoxicity was observed from nitrofen, nitralin, DCPA, Soil Serv 463® and R 7465.

Hedera canariensis - Excepting for both rates of pronamide, phytotoxic effects were minimal. Marginal chlorosis was observed from treatments containing simazine at 0.5 lb/A. Hypericum calycinum - Bypericum calycinum was injured by heat and moisture stresses when first planted. Stunting or necrosis was apparent one month a:f'ter treatment with pronamide, DCPA, Soil Serv li63®, R 71'65, and GS 13638. Pronamide at 8 lb/A was phytotoxic to!!• calycinum. Sedum brevifolium - This succulent was severely injured by GS 13638 at 8 lb/A, less so at 2 lb/A. Suppression appeared to accumulate from R 71i65 at 4 and 8 lb/A. Simazine plus nitralin at 0.5 + 2 lb/A, and simazine plus R 71i65 at 0.5 + 4 lb/A also stunted s. brevifolium. Gazania splendens - Gazania splendens was severely injured with GS 13638 at 8 lb/A. The young newly-set plants became chlorotic from Soil Serv li63® at 6 and 12 lb/A and the combinations containing simazine. Effects had mostly disappeared by October. Vinca minor - Soil Serv li63® at 12 lb/A and GS 13638 at 2 and 8 lb/A caused stunting and burning of new plants. Symptoms were observed with pronamide at 2 and 8 lb/A, nitralin at 2 lb/A, DCPA at 8 lb/A, simazine plus nitralin at 1/2 + 2 lb/A, simazine plus R 71i65 and from GS 13638 at 2 and 8 lb/A. Phyto­ toxicity evaluations were low, however, except for pronamide at 8 lb/A.

Hedera helix - Hedera helix was hardy, showing little stunting or burning from spray applications, except for pronamide at 8 lb/A which appeared to cause severe stunting a:f'ter the second application.

Turfgrass mix and Dichondra - There is little selectivity of the herbicides used for these two plants, both being sensitive.

..' 30

Results - Weed ControlY

Summer Weeds Winter Weeds Months Months After Application After Second Application -- Herbicide Lb/A 1 2 5 l 3 5 8 pronamide 2 8.o 7.0 7.5 8.4 5.5 5.0 2.5 pronamide 8 9.4 8.7 9.0 9.5 7.5 5.8 3.7 nitrofen 4 9.7 9.3 8.2 9.7 7.0 6.o 4.2 nitrofen 8 9.8 9.0 8.7 9.4 8.o 7.5 7.2 nitralin 2 8.6 8.5 9.0 9.3 8.6 8.5 7.5 DCPA 8 8.o 8.o 8.5 8.1 5.0 5.5 5.5 Soil Serv 463® 6 9.2 7.2 7.7 9.4 7.0 7.0 6.7 Soil Serv 463® 12 10.0 9.7 8.7 9.7 8.2 8.o 8.2 R 7465 4 8.8 8.o 9.2 9.9 9.8 9.8 9.7 R 7465 8 9.3 8.7 9.5 9.9 9.9 9.8 10.0 simazine + 1/2 + 2 9.9 10.0 10.0 10.0 10.0 10.0 9.7 nitralin simazine + 1/2 + 2 10.0 9.7 9.2 9.8 9.8 9.8 9.7 trifluralin simazine + 1/2 + 4 9.9 9.5 10.0 10.0 10.0 10.0 10.0 R 7465 GS 13638 2 9.6 8.7 9.2 10.0 8.8 8.o 6.7 GS 13638 8 9.9 9.3 9.2 10.0 9.8 9.8 9.0 control 1.2 1.2 6.7 6.8 o.o 1.2 1.2

Weeds Present common groundsel pigweed shepherds purse misc. grass filaree sowthistle bull mallow lambsquarter henbit chickweed

, y average of 4 replications g/ ratings: 0 = no control; 10 = complete control 31

SUMMARY

Woody Ornamentals

Two trials were established in ornamentals grown in containers and three in field grown woody plants. One container trial was established principally for OXalis corniculatus control. Two herbicides and one herbicide combination gave excellent oxalis control. Linuron at 1,2, and 4 lb/A and a combination of 1 lb of simazine plus 4 lb/A of CGA 10832 gave excellent postemergence control. Residual control was achieved with linuron and preemergence control was achieved with oryzalin. Linuron at 4 lb/A gave severe injury to both ornamental species whereas the other herbicides or linuron at 1 and 2 lb/A were not excessive. Raphiolepis indica also was injured by weed competition.

One trial was established for herbicide tolerance and control of lesser­ seeded bittercress in container grown ornamentals. R 7li65, alachlor, and simazine plus R 7li65 appeared to give some control of bittercress. Pronamide did not control lesser-seeded bittercress. Nitralin, R 7li65 at 4 lb/A, alachlor at 2 lb/A, and the simazine plus R 7li65 (0.5 + 4) were the safest to use on the 6 newly planted plant species. All herbicides reduced the top fresh weights of newly planted Buxus japonica.

Two trials were conducted on Eucalyptus cinerea and one on Wrtus communis 'compacts' in the field at 2 locations in California. These plants are grown for their decorative foliage. A low rate of simazine plus nitralin or trifluralin appeared safe in these trials. Fluorodifen, SAN 9789 or oxidiazon may also give good control with safety in some locations. 32

O:X:alis corniculatus control in container grown ornamentals and tolerance of Pinus thunbergii and Raphiolepis indica to several herbicides. Elmore, c. L., L. Frey, and E. Roncoroni. O:X:alis corniculatus, creeping wood sorrel, is one of the major and more persistent weed pests in growing container orna­ mental plants. Because of extensive seeding from a single plant and running rootstocks the plant is very prolific and difficult to control through cul­ tural management. If only a few plants are allowed to seed in a nursery, soon the entire nursery can bec~me infested.

Until the present the only chemical means of control has been non-selec­ tive to desirable plants except with a few species notably orchids and palms with the soil persistent herbicides simazine and monuron. Soil :fumigation with methyl bromide is effective as a preplant treatment, but once plants are established this treatment cannot be used without killing desirable plants.

Young transplanted gallon containers of Pinus thunbergii and Raphiolepis indica were selected to screen several herbicides for oxalis control. Con­ tainers of E• thunbergii were selected with oxalis present to treat post­ emergence. Four replications of each species were treated with a broadcast spray on April 2, 1971, with a C~ pressure sprayer. Treatments were band watered innnediately after treatment. All weeds were pulled from the contain­ ers after the first evaluation on May 7, 1971. Seed was scattered over the complete trial to assure oxalis reinfestation for preemergence activity. Subsequent evaluations were made as preemergence treatments realizing that soil in the f• thunbergii containers had been disturbed. O:X:alis control and phytotoxicity evaluations are summarized in Tables 1 and 2. The soil was a modified u.c. mix containing 16.9% organic matter, 88°/o sand, 6% silt, and 6% clay. Results An herbicide that gave excellent preemergence activity (Table 1) with apparent safety to both ornamental species was oryzalin as shown in Table 2. No postemergence effect was observed. A rate of 2 lb/A gave 70°/o control at 4 months; with the 4 lb, 80°/o; and 8 lb, 90°/o• From previous tests, ory­ zalin has been shown to be safe on 4 other species as well. Linuron gave excellent postemergence and residual preemergence control of Q• corniculatus at all rates of application. After 4 months, 1 lb/A indicated reduced control; however, 2 and 4 lb/A were still giving 100% control. There was some injury evident at all rates on f• thunbergii, only slight injury on~· indica except at 4 lb/A. None of the other herbicides or combinations gave the residual control of linuron or oryzalin. Activity was found with simazine in the combina­ tion with CGA 10832; however, simazine has previously controlled oxalis, thus this combination does not appear to be an improvement. Other herbicides that appear to be safe on R. indica and P. thunbergii are R 7465, alachlor (which is registered for ornamentals), A '8'20, and terbutryn in this study. Cooperator: Oki Bros. Nursery, Sacramento, California. 33

Table 1. Control of OXalis corniculatus by several herbicides and combinations of herbicides at various intervals after application.*

Months After Application Rate 1 mo 2 mo 3 mo 4 mo ·Herbicide Lb/A Postemergence Preemergence R 7465 4 1.5 5.8 5.0 4.o R 7465 8 o.o 7.2 6.8 4.o R 7465 32 1.8 8.o 7.6 5.0 oryzalin 2 1.2 5.5 8.1 7.0 oryzalin 4 o.8 6.5 9.2 8.o oryzalin 8 0.5 9.2 10.0 9.0 alachlor 2 1.2 1.2 1.5 o.o alachlor 4 0.2 1.8 3.5 o.o alachlor 8 3.2 o.8 2.2 2.0 A 820 2 2.5 1.5 3.8 1.0 A 820 8 0.5 1.8 4.5 3.0 nitralin 2 0.2 3.0 6.o 3.0 terbutryn 1 0.2 o.o 0.2 o.o terbutryn 2 3.2 o.o o.o o.o terbutryn 4 6.o o.8 4.2 1.0 linuron 1 10.0 6.8 9.4 7.0 linuron 2 10.0 10.0 10.0 10.0 linuron 4 10.0 10.0 10.0 10.0 u 27267 2 o.o o.o 1.5 o.o u 27267 4 o.8 0.2 o.o o.o u 27267 8 o.8 5.8 L2 3.0 control-weeded 0.2 o.o 8.1 o.o control-nonweeded 1.8 0~5 7.8 2.0 simazine + nitralin 0.5 + 2 3.8 5.5 1.0 5~0 simazine + CGA 10832 0.5 + 2 5.5 1.8 9.0 1.0 simazine + CGA 10832 1 + 4 9.0 2.5 4.8 4.o MON 097 2 3.8 3.5 7.8 1~0 MON 097 8 1.5 o.8 5.2 2.0 U 27267 + simazine + nitralin 1.5 5.8 4.8 4.o Qverspray

* weed control: O = no control; 10 = complete control Table 2. Phytotoxicity of several herbicides on Raphiolepis indica and Pinus thunbergii grown in containers for 3 months before treatment.*

P. thunber~ii R. indica Herbicide Lb/A l mo 3 mo 4 mo 6 mo l mo 3 mo 4 mo R 7¼65 4 1.2 0.2 o.o o.o o.8 1.2 o.o R 7¼65 8 o.o o.o o.o o.o o.8 1.2 o.o R 7¼65 32 o.8 o.o 1.0 o.o 1.5 1.0 1.0 oryzalin 2 1.0 o.o o.o o.8 o.o 1.5 2.0 oryzalin 4 o.o 0.2 o.o 0.5 0.5 0.2 o.o oryzalin 8 0.2 o.o o.o 0.2 o.8 0.5 o.o alachlor 2 o.o o.o o.o o.o o.o 0.5 1.0 alachlor 4 0.5 1.0 o.o o.o 0.2 o.8 1.0 alachlor 8 0.5 1.8 2.0 o.o 0.5 0.2 1.0 A 820 2 1.2 0.5 o.o 1.8 o.o 3.8 3.0 A 820 8 o.o o.o o.o 0.5 o.o 1.0 1.0 nitralin 2 0.5 0.5 o.o o.o o.o o.8 o.o terbutryn 1 1.0 1.2 o.o o.o o.o 1.0 o.o terbutryn 2 2.0 1.2 o.o o.o o.o o.8· o.o terbutryn 4 1.5 1.2 o.o o.o o.o o.8 o.o linuron 1 1.5 0.5 o.o o.o o.o 2.0 3.0 linuron 2 2.0 1.5 1.0 3.0 o.o 3.2 5.0 linuron 4 4.8 1.2 o.o 7.0 o.o 6.5 6.o u 27267 2 0.2 0.5 o.o o.8 o.o 1.5 1.0 u 27267 4 o.o 1.5 o.o o.o o.o 2~0 1.0 u 27267 8 2.5 1.2 o.o 7.5 o.o 2.2 6.o control-weeded 1.0 1.0 o.o o.o o.o 2.5 1.0 control-nonweeded 0.5 1.5 o.o o.o o.o 5.8 o.o simazine + nitralin 0.5 + 2 1.2 0.2 o.o o.8 0.5 o.8 o.o simazine + CGA 10832 0.5 + 2 o.8 o.8 1.0 o.o o.o 1.8 o.o simazine + CGA 10832 1 + 4 1.0 o.8 o.o o.o o.o 0.5 1.0 MON 097 2 1.5 o.8 o.o 0.2 o.o 1.0 1.0 MON 097 8 3.0 0.5 2.0 1.0 o.o 2.2 1.0 U 27267 + simazine + nitralin 0.5 2.2 o.o 2.2 o.o 2.8 3.0 overs pray

* phytotoxicity: 0 = no effect; 10 = dead plants 35

Control of bittercress with five preemergence herbicides and tolerance on six container grown ornamentals. Farnham, D. s. and c. L. Elmore. Six species of ornamental shrubs were planted February 19, 1971, from liners into a modified u.c. potting mix (soil analysis: 7.4% o.m., 9o'fo sand, 5% silt, 5% clay) at Leonard Coates Nursery, Watsonville. The herbicides were applied as a broadcast spray and washed off the foliage by hand sprinkling after treatment. Each treatment was replicated 10 times.

Evaluation of weed control was done by counting the weeds (by species) present in the containers (Table 1). Injury was observed both as phytotox­ icity evaluations (Table 2) and by a plant growth index (PGI) measurement (Table 3). The plant growth index.is a measurement in em's according to the formula: PGI (Plant Growth Index)= height of plant (cm) x diameter of plant (cm) 2

These (PGI) measurements were taken May 6, 1971, and July 28, 1971. The differences between the two (PGI) measurements shown in Table 3 indicate the relative effects by the herbicide on growth of the plant.

After 8 months Buxus japonica was selected for fresh weight measurements (Table 4). The plants were cut at the ground line and weighed. The con­ tainers were then prepared for a bioassay using Avena sativa (cultivated oats). A section 3/4 inch in width was removed from the side of the container from six replications of each treatment. The top of one container was placed inside the top of another container of that treatment. Oats were planted October l2, 1971, in the exposed soil from the cut area along the side of each container at 1/4 inch intervals. Effects from the herbicide treatments were observed October 20, 1971.

Growth Aspects As indicated by a comparison of the plant growth indexes, some herbicides affected various ornamental species differently. These indices seemed to give an excellent description of effects of the herbicides on the plants.

Nitralin at 2 lb/A did not appear to effect either juniper specie or Grevillea noellii (Table 1). There was a reduction in growth, however, of ~ buxifolia and Buxus japonica compared to an untreated control. This same effect appeared from a visual phytotoxicity evaluation with!!· buxifolia (Table 2) as well as Erica canaliculata 'rosea' but not with 1!• Japonica. At rates of 4 and 8 lb/A, R 7li65 did not appear to effect l• sabina ~amariscifolia or~- noellii; however, other species showed reduced growth. Visual evaluation indicated H. buxifolia was severely affected, particularly at the 16 lb/A rate. The fresh weight of the tops of B. japonica was signi- ficantly reduced at the 16 lb/A rate. - Alachlor appeared to effect growth of all plants except G. noellii at the 8 lb/A rate; however, there were only slight differences between the 2 lb/A rate and the untreated plants. Pronamide reduced the growth of all plants at all rates except l· chinensis Ffitzeriana 'aurea' and Q.• noellii at the 2 lb/A rate. These evaluations were evident with visual observations with the exception of J. chinensis pfitzeriana 'aurea'. Although~· canaliculta 'rosea' was not - measured, phytotoxicity evaluations would indicate injury with all rates of pronamide.

When simazine was added at 0.5 lb/A to R 7465 it would appear injury was increased to H. buxifolia {Table 2) and a growth reduction (Table 3 and 4) occurred on~- japonica.

After 8 months in the nursery, pronamide was the only herbicide indicat­ ing significant residue to injure oat seedlings in a bioassay. The herbicides nitralin, R 7465, alachlor, and simazine at the rates in this trial were not apparent in this bioassay.

Cooperator: Leonard Coates Nursery, Watsonville, California.

Table 1. Average weed count per container four or five months after treatment.

Average Weed Count Bittercress ·oroundsel Willow Herbicide Lb/A limo 5 mo 4 mo 5 mo 4 mo 5 mo nitralin 2 3.0 1.0 o.o 0.1 o.o o.o simazine + R 7465 0.5 + 4 o.o 1.4 o.o 0.2 o.o o.o R 7465 4 o.o 2.0 0.1 o.o o.o 0.1 R 7465 8 o.o 1.4 o.o 0.1 o.o o.o R 7465 16 o.o 0.7 o.o o.o o.o o.o alachlor 2 0.7 3.6 o.o 0.1 0.1 0.1 alachlor 8 o.o 1.9 0.1 0.1 o.o 0.2 pronamide 2 2.5 12.8 o.o 0.2 0.3 0.2 pronamide 4 1.7 16.5 0.1 o.o o.o 0.1 pronamide 8 o.o 4.o 0.1 o.o o.o o.o control 2.8 3.0 0.1 0.1 1.5 o.o 37

Table 2. Average phytotoxicity to six container grown ornamentals four months after treatment with several herbicides.

Rate Average Phytotoxicity By Plant Species* Herbicide Lb/A A B C D E F n1tral1n 2 0.1 o.o 1.2 1.1 o.o o.o simazine + R 7~5 0.5 + 4 0.2 o.o 2.3 o.4 o.o o.o R 7~5 4 o.o o.o 1.2 o.o o.o 0.2 R 7~5 8 o.o o.o 1.8 o.4 o.o 0.5 R 7~5 16 1.3 o.o 5.8 0.9 o.o o.6 alachlor 2 0.1 o.o 1.1 0.7 o.o 1.0 alachlor 8 0.7 o.o 7.2 1.4 o.o 1.0 pronamide 2 0.1 o.o 8.6 1.3 0.5 o.4 pronamide 4 1.7 o.o 9.8 2.5 1.5 1.4 pronamide 8 2.3 o.o 9.7 4.5 2.8 2.4 control o.o o.o o.o 0.1 o.o o.o

* phytotoxicity: 0 = no effect; 10 = dead plants A Juniperus sabina tamariscifolia D Erica canaliculata 'rosea' B Juniperus chinensis pfitzeriana 'aurea' E Grevillea noellii C Hebe buxifolia F Buxus japonica

Table 3. Difference in plant growth index during ten weeks of growth of five species of ornamental shrubs as affected by several herbi­ cide treatments.

Rate Plant Growth Index (FGI) In Cm's Herbicide Lb/A A B C D E nitralin 2 275.3 97.8 379.8 113.6 16.7 simazine + R 7~5 0.5 + 4 289.6 52.3 363.4 114.1 14.9 R 7~5 4 278.7 4o.o 351.5 128.0 18.9 R 7~5 8 248.3 33.5 357.8 107.8 17.1 R 7~5 16 169.4 22.0 430.2 59.6 15.4 alachlor 2 241.0 57.5 316.7 126.3 16.4 alachlor 8 170.5 21.0 535.3 ~-4 10.5 pronamide 2 -43.4* 84.3 391.7 -14.6 10.7 pronamide 4 -36.9 23.3 253.8 -17.2 5.2 pronamide 8 -44.o 25.6 112.7 -17.9 1 .. 8 control 240.2 68.7 348.1 151.1 21.1

* minus numbers indicate a high percentage of dead plants

A Juniperus sabina tamariscifolia D Hebe buxifolia B Juniperus chinensis pfitzeriana 'aurea' E Buius Japonica C Grevillea noellii Table 4. Effect of several herbicides on Buxus japonica as measured by the fresh weight of the tops eight months after application.

Rate Fresh Weight Herbicide Lb/A (gms) nitralin 2 4.8 simazine + R 7¼65 0.5 + 4 5.7 R 7465 4 9.8 R 7465 8 7.8 R 7465 16 5.9 alachlor 2 7.4 alachlor 8 3.6 pronamide 2 8.4 pronamide 4 2.6 pronamide 8 o.6 control 11.4

Effect of several herbicides and herbicide combinations on n~wly planted Eucalyptus cinerea seedlings. Farnham, D. s. and c. L. Elmore. Eucalyptus cinerea is grown by the cut flower industry for its decorative foliage which is used fresh or dried. Since these trees are pruned severely each year to produce decorative juvenile foliage, weeds become a problem around the trees and between the rows. Cultivation injures the surface feeding roots; thus it would be beneficial to use chemicals to control weeds.

This trial was established March 28, 1971, in newly planted seedlings, which were approximately 6 to 8 inches in height. Two plants were planted March 24, 1971, against a redwood post for support. There were 6 plants per each replication. Each treatment was replicated 3 times. All herbicides were applied as a broadcast spray in 100 gallons of water per acre with a C~ pressure sprayer. The area was sprinkler. irrigated within one hour of treatment. The soil was a sandy loam soil with the following analysis: 0.34% o.m., 67~ sand, 24% silt, 9% clay. Weed control evaluations and plant phytotoxicity ratings were made at various times after treatment. Two months after the initial applications of the preemergence herbicides, amino triazole was oversprayed on the entire trial.

The combination materials containing diuron or simazine with nitralin or trifluralin gave outstanding long residual weed control. However, severe injury was evident where diuron was used. Injury was observed when simazine was added to the combination with nitralin or trifluralin, but it was not severe. The plants so treated established themselves and at 6 months, no effects were observed.

Fluorodifen, S 9789, oxidiazon, and the 4 lb rate of pronamide also gave excellent weed control at 2 months when the area was oversprayed. With the exception of oxidiazon, no injury was observed with these treatments even at high rates. 39

Weed control with nitrofen, Soil Serv 463®, oryzalin or R 7465 was not commercially satisfactory as shown in Table 2.

It would appear that a low rate of simazine could be used in combina­ tion with either nitralin or trifluralin in young Eucalyptus cinerea with only minor symptoms. other herbicides with promise are fluorodifen, SAN 9789 and possibly a lower rate of oxidiazon.

Cooperator: Tom Tolan, Soquel, California

Table 1. Phytotoxicity from several herbicides to seedling Eucalyptus cinerea at 1, 2, and 6 months after application in a sandy, loam soil.

Rate Months After Application Herbicide Lb/A .1 mo 2 mo l5 mo simazine + nitralin 1 + 4 1.6 1.0 o.o simazine + trifluralin 1 + 4 2.0 1.7 0.3 diuron + nitralin 1 + 4 7.3 4.3 1.3 nitrofen + chlorpropham 2 + 2 o.6 o.o o.6 nitrofen 2 o.o o.o o.6 nitrofen. 4 o.o 1.3 o.6 fluorodifen 2 o.o o.o o.o fluorodifen 4 o.o 0.3 o.o Soil Serv 46 '3® 2 o.o o.o o.o Soil Serv 463® 8 o.o o.o o.o oryzalin 1 o.o o.o o.o oryzalin 4 o.o 0.3 o.o SAN 9789 1 0.3 1.0 0.3 SAN 9789 4 1.0 2.3 1.0 oxidiazon 4 o.6 0.3 0.3 oxidiazon 4 4.3 2.0 o.o R 7465 1 0.3 0.7 o.o R 7465 4 o.o o.o 0.3 pronamide 1 o.o 0.7 o.o pronamide 4 o.o o.o o.o control o.o o.o o.o

phytotoxicity: 0 = no effect; 10 = dead plants 40

Table 2. Weed control with several herbicides and herbicide combina- tions in seedling Eucalyptus cinerea plantings.

Rate 1 Month Average Herbicide Lb[A Chickweed Sowthistle Mustard Dock lmo2mo simazine + nitralin 1 + 4 10.0 8.3 9.6 7.6 9.0 9.7 simazine + trifluralin 1 + 4 10.0 8.8 9.3 8.3 9.1 9.1 diuron + nitralin 1 + 4 10.0 8.6 10.0 9.0 8.3 9.5 nitrofen + chlorpropham 2 + 2 10.0 8.3 10.0 9.2 7.3 5.0 nitrofen 2 7.3 6.3 5.0 10.0 3.0 5.3 nitrofen 4 10.0 4.6 5.3 10.0 5.6 7.7 fluorodifen 2 3.0 8.3 8.3 9.3 6.3 6.3 fluorodifen 4 8.o 8.3 9.6 10.0 9.0 8-3 Soil Serv 463® 2 8.6 5.0 6.3 6.6 2.6 3.7 Soil Serv 463® 8 10.0 7.0 9.0 8.6 5.3 4.7 oryzalin l 9.0 5.3 3.6 6.3 3.0 6.o oryzalin 4 10.0 8.6 9.3 8.o 7.0 7-3 SAN 9789 l 10.0 8.6 9.3 9.3 7.0 8.o SAN 9789 l 10.0 8.6 9.3 9.3 7.0 8.o oxidiazon 4 8.3 10.0 10.0 9.2 9.1 8.8 oxidiazon 4 6.3 9.2 10.0 10.0 9.3 8.7 R 7465 1 7.6 2.6 0.3 1.0 1.0 5.0 R 7465 4 7.0 6.o 4.6 6.o 2.3 4.o pronamide l 10.0 5.6 9.3 9.2 6.o 5.0 pronamide 4 10.0 5.0 9.0 8.o 5.6 8.o control o.o o.o o.o o.o o.o o.o

weed control: 0 = no control; 10 = complete control

Control of annual weeds in Eucalyptus cinerea and Myrtus communis 'compacta' in the field. Besemer, s., A. Lange, and c. L. Elmore. Two trials were established March 19, 1971, on EucalyEtus cinerea and !1¥:rtus communis 'compactd planted from gallon containers in a Folbrook sandy loam soil. The herbicides were applied with a CO2 pressure sprayer in 100 gallons of water per acre as a directed spray. Plot size was 8 :ft x 3 :ft and each was replicated 4 times. The area was sprinkler irrigated. Weed control and phytotoxicity evaluations were made April 7, 23, and May 20. 41

Weed control and pbytotoxicity from several herbicides and herbicide combinations on Eucalyptus cinerea and I-eyrtus comrnunis 'compacta'.

Eucalyptus cinerea Myrtus communis Weed Control Ph~otoxici t;y- Weed Control Rate (days}* days)** (days)* Herbicide Lb/A 19 35 19 19 35 62 simazine + trifluralin 1 + 4 3.2 9.0 o.o 8.2 9.9 9.9 simazine + nitralin 1 + 4 2.8 7.5 o.o 8.2 10.0 10.0 nitralin + CIPC 2 + 2 2.8 7.0 O.·O 3.5 6.o 4.2 nitrofen 1 3.0 6.5 o.o o.o 4.8 2.5 nitrofen 4 0.5 6.2 o.o 2.8 6.o 4.8 fluorodif'en 1 o.o 5.8 o.o 2.0 6.o 3.0 f'luorodifen 4 0.5 6.8 o.o 0.5 7.8 6.5 Soil Serv 463® 2 o.8 4.o o.o 1.2 5.8 4.o Soil Serv 463® 8 2.0 7.0 o.o 8.5 9.0 9.0 oryzalin 1 0.2 6.2 o.o o.o 5.5 4.8 oryzalin 4 o.8 6.5 0.2 o.o 6.o 6.5 diuron + nitralin 1 + 4 2.2 8.0 o.o 9.5 9.9 9.8 SAN 9789 1 1.0 5.0 o.o 2.0 6.2 5.5 SAN 9789 4 6.8 6.8 o.o 6.8 7.8 9.0 oxidiazon 1 2.5 7.2 2.5 5.5 7.2 5.8 oxidiazon 4 6.8 8.2 3.8 8.2 9.5 9.4 R 7465 1 o.o 5.2 o.o o.o 6.5 4.8 R 7465 4 0.5 6.2 o.o 0.5 5.8 4.8 control o.o 4.o o.o 0.2 3.8 0.5

* 0 = no control; 10 = complete control ** 0 = no ef'f'ect; 10 = dead plants All data are means of 4 replications 42

SUMMARY

Christmas Trees

Three trials were established in one county to study the control of sheep sorrel in Monterey pines.

Dicamba at 2 lb/A gave excellent control when applied in the fall (September). Good early control was achieved from spring application but residual control declined.

Pronamide gave some control when applied in March; however, poor con­ trol was achieved from fall applications.

Endothall gave good control early, but the sheep sorrel regrew in about 3 months. Sheep sorrel control in Monterey pines. Johnson, E. J. and c. L. Elmore. Sheep sorrel is a perennial weed distributed throughout California. A common practice in plantation-grown Christmas trees in the state is to use simazine or atrazine for preemergence weed control. Neither of these herbi­ cides effects sheep sorrel which consequently becomes very abundant with the lack of competition.

Three trials were conducted in 1970-71 at Ano Nuevo Ranch in San Mateo County. Trial number 1 involved 3 materials applied to single trees and replicated 4 times. Trial number 2 involved the same materials applied to 2 trees in each of 3 replications. In the third trial we applied 2 materials at 3 rates to 2 trees in each of 3 replications. X-77 at 1 lb per 100 gallons of water was used with all herbicides. Refer to Tables 1, 2, and 3. Endothall at the 4 lb/A rate gave a good initial knockdown but the sorrel grew back within 3 months. Pronamide was only effective when applied during the winter, in this case on March 2, 1971. At the 6 lb/A rate, good control was achieved for 7 months. Dicamba appeared to be the best material in these trials. In trial number 2, when applied in September at 2 lb/A, excellent control was maintained for 1 year. Because this was not the case when applied at other times of the year, it would appear that timing may be as critical with dicamba as it is with pronamide. In trial number 3 treated March 2, 1971, a slight chlorosis was observed in trees in the dicamba plots. No twisted needles were observed. All trees outgrew this condition within a short period of time. No phytotoxicity was observed with pronamide or endothall.

Table 1. Sheep sorrel control in Monterey·pines treated May 21, 1970, and retreated September 2, 1970, average of 4 replications.

Rate July August October October December February Herbicide Lb/..A 2 17 2 29 15 11 dicamba 0.5 3.2 1.5 4.8 3.8 3.0 3.0 dicamba 1 6.5 4.2 6.o 5.2 6.2 6.o dicamba 2 9.2 8.2 9.0 9.8 9.8 9.5 endothall 2 7.0 1.2 7.0 3.2 3.2 1.8 endothall 4 7.5 o.o 8.5 4.2 5.0 2.2 pronamide 2 0.5 0.2 1.8 0.5 1.5 1.0 pronamide 4 0.5 o.8 1.2 o.8 1.0 0.5 pronamide 8 1.0 o.o 0.2 1.0 5.8 5.0 control o.o o.o o.o o.o o.o o.o

) I L...... ___ 44

Table 2. Sheep sorrel control in Monterey pines treated September 2, 1970, average of 3 replications.

Rate October October December February April July Herbicide Lb/A 2 29 15 11 30 28 dicamba 0.5 3.7 3.3 5.3 2.3 3.7 1.7 dicamba 1 5.7 5.7 5.3 5~0 3.0 3.3 dicamba 2 8.3 9.0 8.3 6-3 7.0 8.3 endothall 2 5.7 1.7 o.8 o.o o.o 1.0 endothall 4 8.3 6-3 4.3 3.3 1.3 3.3 pronamide 2 0.3 0.3 1.7 0.3 1.0 o.o pronamide 4 0-3 0.3 o.8 o.o o.8 o.o pronamide 6 o.o 1.3 2.3 1.3 1.3 2.3 control 0.7 0.7 1.0 0.3 o.o 0.3

Table 3. Sheep sorrel control in Monterey pines treated March 2, 1971, average of 3 replications.

Rate March April May July Herbicide Lb/A 31 30 18 28 dicamba 0.5 7.0 3.0 1.3 o.o dicamba 1 6.o 4.3 2.3 2.0 dicamba 2 8.3 8.o 6.o 1.3 pronamide 2* 1.8 1.8 1.0 o.o pronamide 4* o.8 1.8 2.0 2.0 pronamide 8 1.8 4.3 2.8 5.8 control* 1.8 1.3 0.3 0.3

* Note: sheep sorrel in the 3rd replication of these treatments seemed to be dying off from causes other than herbicides used in the trial. SUMMARY

Turf (Grass and Dichondra)

During the 1970-71 season there were twelve trials in eight counties in California. Four of these trials were for the control of annual bluegrass, six for preemergence control of crabgrass, one for the control of tall fes­ cue, and one for the control of goosegrass.

Annual Bluegrass - Pronam.tde and oryzalin both controlled annual blue­ grass in bermudagrass turf when applied after the annual bluegrass was well established. Phytotoxicity to the bermudagrass was obvious at 2 months after application with 3 and 6 lb/A of oryzalin at one location. One to 1.5 lb/A of pronamide is required for control used alone or in combination with bensulide.

In a Merion-Newport bluegrass sod only a combination of endothall (0.75 lb) plus bensulide (10 lb/A) gave connnercial control. Pronamide was severely injurious to bluegrass.

Crabgrass - The standard preemergence herbicides continue to be the out­ standing materials. OXidiazon in these tests appeared to have promise as a crabgrass herbicide. The emulsifiable concentrate formulation was used in all tests with some phytotoxicity, thus further testing is required with a granular formulation. Also the 4 lb/A rate of·CGA 10832 or AN 56477 appeared to give excellent control in most tests. Injury with these materials was very slight.

In an early postemergence crabgrass trial at one location, A 820 at 6 lb/A appeared to give similar control as benefin at 3 lb/A. Both of these treatments were not as good as bensulide at 15 lb/A.

When NC 8438, MSMA, or nitrofen are applied with bensulide postemergence {approx. 3 leaf stage) to crabgrass, good control is achieved through 132 days after application.

Tall Fescue - Two herbicides,were applied for the control of established tall fescue in a golf course fairway. Terbutol at 10, 20, or 40 lb/A or terbacil at 1/16, 1/8, or 1/4 lb/A did not control tall fescue.

Dichondra - DSMA at 8 lb/A treated at approximately 3 weeks apart gave the best control of Eleusine with the least injury to seed dichondra. MSMA and dalapon at the same rate was somewhat less satisfactory. Dalapon caused severe injury at 8 plus 8 lb/A and unacceptable injury even at 4 plus 4 lb/A. Monuron did not control the goosegrass. Hairy crabgrass was controlled with a single application of DSMA or MSMA, or 2 applications of dalapon. Dalapon successfully controlled sprangletop whereas there was poor control with DSMA, MSMA, or monuron. 46

Control of annual bluegrass in turf. Elmore, c. L., L. Frey, K. Gowans, and J. Van Tulro. Annual bluegrass is found as a weed in the fall and winter months, grows during the cool winter months, matures and normally dies during the summer. If the turfgrass areas are irrigated frequently, this grass can be found throughout the year.

Cultural control is very effective by controlled irrigation. The soil surface may be allowed to dry in the fall of the year when annual bluegrass is germinating or in early summer to eliminate existing populations. The roots of perennial bluegrass are much deeper and can tolerate this drought stress whereas annual bluegrass cannot. Increased mowing height will greatly reduce annual bluegrass invasion as well as not aerating in late August and September when annual bluegrass is germinating.

Using the proper cultural conditions can reduce or often eliminate annual bluegrass from a turf. However, often the best cultural conditions for con­ trol do not coincide with present management practices; thus annual bluegrass becomes a pest.

Preemergence control of annual bluegrass has been effectively worked out for many turf situations and is widely used. However, there are times when a postemergence chemical control method is needed. This series of experiments were conducted to find chemicals for annual bluegrass control under various cultures.

In 1970-71 two studies were conducted to evaluate postemergence herbi­ cides for annual bluegrass control in bluegrass sod. Two studies were also conducted on bermudagrass turf using preemergence herbicides alone or in com­ bination with postemergence herbicides.

Study One Five herbicides were evaluated and compared to two standards, bensulide and benefin for control of annual bluegrass and crabgrass in Tifgreen bermuda­ grass turf at the state and county arboretum in Los Angeles. Treatments were hand sprayed on February 25, 1970, on plots replicated four times. The initial evaluations were made on annual bluegrass and subsequent evaluations on crabgrass. Phytotoxicity evaluations were made 2 and 5 months after application. 47

Table 1. Control of annual bluegrass and crabgrass and phytotoxicity to Tifgreen bermudagrass turf.

1/ Weed Control- Phytotoxicit.)/ Rate Months After Application Months After Application Herbicide Lb/A 2(a} 3(a} 3(~) i5(~) 9(~) 2 5 oryzalin 2 7.3 5.6 10.0 6.6 7.2 3.0 o.o oryzalin 3 8.5 7.6 9.9 8.4 6.5 5.0 o.o oryzalin 6 9.5 9.0 10.0 9.8 9.4 7.5 o.o pronamide 2 8.8 7.3 7.8 5.5 4.1 3.2 o.o pronamide 4 9.8 9.6 8.8 7.4 4.4 3.5 o.o BASF 2903 4 3.0 4.o 5.3 4.4 1.9 0.7 o.o BASF 2903 8 3.3 4.o 5.4 5.0 2.6 1.0 o.o bensulide 15 4.o 4.o 9.0 8.6 7.1 0.7 o.o benefin 3 5.3 5.4 8.8 7.7 5.7 2.5 o.o control 3.3 4.o 6.o 5.0 2.1 0.5 o.o

y weed control: 0 = no effect; 10 = complete control (a) annual bluegrass evaluations (c) crabgrass evaluations

?./ phytotoxicity: 0 = no injury; 10 = dead turf

0ryzalin and pronamide gave early control of annual bluegrass with oryzalin giving good residual crabgrass control. BASF 2903 did not injure bermudagrass turf; neither did it give effective control. Early injury was evident on the bermudagrass with oryzalin at all rates. Pronamide and benefin also showed early stunting of the turf. At 5 months after application, no visual effects could be observed with any treatment. Bensulide did not control annual bluegrass because it was already established.

Study Two: Several herbicides were evaluated on a Merion-Newport bluegrass sod which had been planted early in June, 1970. The herbicide applications were applied as a broadcast spray on November 13, 1970, on a wet, poorly drained area. Terbutol and benefin were applied, followed by a 5 minute irrigation. The remaining treatments were applies to wet turf following the irrigation. Air temperature was approximately 70 F. at application. Control of annual bluegrass and phytotoxicity to the bluegrass sod were evaluated December 10 and 23, 1970, and February 8 and April 1, 1971.

I LI 48

Table 2. Postemergence control of annual bluegrass and pbytotoxicity of several herbicides in a Merion-Newport bluegrass sod.

Rate Weed Control]/ p totoxicit 2/ Herbicide Formul. Lb/A 12710 12723 278 r~-71 12 10 12 23 2 1 endothall potassium 0.75 5.5 6.8 3.5 5.2 2.2 1.8 1.3 1.2 salt endothall 1.5 8.2 8.5 7.5 8.o 4.5 4.5 3.8 2.8 endothall 3.0 9.5 9.8 9.5 9.4 7.5 8.2 7.5 4.8 MSMA Ansar 529 3.0 1.0 1.8 0.5 2.2 o.8 o.8 1.0 0.5 4#/gal MSMA 6.o 2.2 1.0 0.2 2.8 o.o o.o o.o 0.2 terbutol 80C)b WP 15.0 1.0 3.0 o.o 3.0 2.0 2.2 3.8 5.5 benefin 1. 5 lb/ 3.0 1.8 2.5 0.2 1.5 0.2 o.8 o.8 o.8 gal benefin + endothall 3.0 + 1.5 8.o 9.3 8.5 8.9 6.8 7.0 5.5 3.8 control o.o 0.2 o.o o.8 0.2 0.5 o.o o.o

~/ weed control: 0 = no effect; 10 = complete control

g/ phytotoxicity: 0 = no effect; 10 = dead turf

Endothall gave good to excellent control of annual bluegrass at 1.5 to 3.0 lb/A on bluegrass sod. At 0.75 lb/A less than adequate control was achieved. At 1.5 lb/A, early injury was very evident and at 3.0 lb/A, severe.

When endothall at 1.5 lb was added to benefin as a preemergence, more injury was noted without an appreciable increase in annual bluegrass control. Terbutol, benefin, or MSMA (monosodium methanearsonate) did not control annual bluegrass in this test. In this young sod, there was injury from terbutol at 15 lb/A. study Three: A new trial was established on January 25, 1971, on a bluegrass sod in the same area as study two to observe pbytotoxicity and annual bluegrass con­ trol with five herbicides or combinations of herbicides. All treatments were applied as a broadcast spray to wet turf with a C~ pressure sprayer at 30 psi in 100 gpa. Air temperature was approximately 65°F. at application. Control of annual bluegrass was evaluated April 1 and May 6, 1971; phytotox­ icity to the bluegrass sod was evaluated February 8, Aprill, and May 6, 1971. Table 3. Annual bluegrass control and phytotoxicity

1/ 2/ Rate Annual Bluegrass Control- ~totoxicitt- Herbicide Lb/A 471 57; 2 471 5T endothall (K salt) 0.75 4.5 4.8 3.0 1.5 1.8 endothall + bensulide 0.75 + 10 7.0 6.2 3.3 1.2 2.0 endothall + benefin 0.75 + 3 5.5 4.8 3.3 1.2 2.2 pronamide 0.25 4.5 2.2 0.5 6.5 8.5 pronamide 0.50 6.5 4.o 0.2 7.0 10.0 nitrofen 5.00 0.5 0.2 o.o 0.2 0.2 nitrofen 10.00 1.5 1.2 0.5 1.2 2.2 nitrofen + bensulide 5 + 10 o.8 o.8 0.5 o.o 1.2 bensulide 10.00 o.8 0.2 0.2 0.2 1.5 benefin 3.00 o.o 0.2 o.o o.o o.o control o.o 0.2 0.2 0.5 0.5

y weed control: 0 = no effect; 10 = complete control

g/ phytotoxicity: 0 = no effect; 10 = dead turf

Annual bluegrass control was less than adequate (Table 3) from all treatments except endothall at 0.75 lb plus bensulide 10 lb/A. Even this combination was marginal when application was made to old annual bluegrass plants as in this trial. Earlier application may have been more effective with endothall or combinations with endothall-benefin or endothall-bensulide. There was some initial pbytotoxicity to Kentucky bluegrass from 0.75 lb/A of endothall; however, this was temporary. Severe injury was evident from pronamide at 0.25 or 0.5 lb/A. This injury was principally from root uptake as indicated by the increase in injury during the evaluation period of the trial whereas endothall was a foliar injury.

Study Four On February 11, 1971, broadcast treatments of two herbicides pronamide and bensulide and combinations of the two herbicides were applied on a Tif'way bermudagrass sod in San Jose, California.- The herbicides were applied in a knapsack sprayer at 30 psi in 50 gpe;. Each plot was replicated 4 times. The trial area was sprinkler irrigated February 13, 1971. The temperature was 71°F. at time of application with a wind of 10-15 mph. Both herbicides were applied on a fertilizer base (Table 4) and w:L thout fertilizer as liquid ~prays. Control of annual bluegrass was evaluated on March 23, April 8, June 25, and November 4, 1971. No treatment appeared to injure the bermuda­ grass. 50

Table 4. Postemergence control of annual bluegrass' in bermudagrass turf.

Rate Annual Bluegrass Control* Herbicide Lb/A 3/23/71 4/8/71 6/25/71 11/4/71 pronamide 0.5 o.8 o.o 4.5 8.2 pronamide 0.75 1.0 1.2 5.0 7.2 pronamide 1.0 1.8 5.0 6.8 8.o pronamide + bensulide 0.5 + 7.5 0.5 1.2 3.0 6.5 pronamide + bensulide 0.5 + 10 0.2 0.5 3.5 7.2 pronamide + bensulide 0.75 + 5 0.5 2.2 4.2 7.8 pronamide + bensulide 0.75 + 7.5 1.0 3.2 5.8 8.5 pronamide + bensulide 0.75 + 10 1.2 1.7 5.0 8.1 pronamide + bensulide 1.5 1.2 4.7 6.2 8.o pronamide + bensulide 1 + 7.5 2.5 7.5 7.8 8.2 bensulide 10 o.o o.o 1.2 4.2 pronamide + bensulide 1 + 10 1.8 6.o 6.8 8.3 pronamide + bensulide 1.5 + 15 3.0 8.2 7.2 8.2 cc 1418** 0.75 + 7.5 2.0 4.1 5.2 8.1 cc 1418* 1.5 + 15 2.8 5.5 8.2 9.1 control o.o o.o 1.8 3.8

* weed control: ,0 = no effect; 10 = complete control ** CC 1418 is a Chevron Chemical Company mix of pronamide + bensulide on a 22-4-4 fertilizer ca~rier.

No postemergence control of annual bluegrass was apparent with bensulide in Tifway bermudagrass turf. Also pronamide did not give ade4uate control at 0.5, 0.75, or 1.0 lb/A by itself. When pronamide was used at 1 lb/A in combination with bensulide at 7.5 lb/A, commercial control was achieved (Table 3). A combination of 1.5 lb/A pronamide plus bensulide at 15 lb/A or the fertilizer additive combination at the same rates also gives better than 70% control of annual bluegrass. With this combination, it is apparent that pronamide is controlling the established annual bluegrass plants, and bensulide is giving preemergence activity. As indicated in Table 4, control of established annual bluegrass plants is a slow procedure with pronamide.

It would be worthwhile to further investigate these combinations, par­ ticularly 1 lb/A pronamide and 7.5 or 10 lb/A of bensulide at various times of the season on younger annual bluegrass plants or if it is desirable to control older plants at the end of the annual bluegrass growing season {March or early April).

Summary: From the testing of herbicides in these trials, it would appear there are two potential treatments for further testing. In warm season grasses {bermudagrass, zoysiagrass) a combination of pronamide plus bensulide could be 4uite satisfactory at 1 lb plus 7.5 to 10 lb/A for postemergence control plus residual preemergence control. In bluegrass turf, endothall should be further tested alone but particularly in combination with bensulide. In 51

these tests, rates of 0.75 to 1.5 lb/A of endothall should be adequate on young annual bluegrass. These rates probably should be maintained to keep adequate safety.

Crabgrass control in turf. Elmore, c. L., K. Mueller, K. Gowans, and B. Fischer. Since hairy crabgrass (Digitaria sanguinalis) and smooth crab­ grass (Q• ischaemum) are common weed problems throughout California, trials were established in four different regions of the state. These four loca­ tions gave different climatic conditions and turf types to test the same herbicides.

The trial locations and application details were as follows.

Location 1. Several preemergence herbicides were applied February 2, 1971, on a bluegrass-bentgrass turf at the Los Gatos Civic Center in Los Gatos, Galifornia. The herbicides were applied with a Champion knapsack sprayer at 30 psi in a volume of 100 gpa. The plot size was 5 ft x 10 ft and was replicated 4 times. The area was sprinkler irrigated immediately after application to wash the herbicide from the foliage. Evaluations for pbytotoxicity were made February 14, March 23, and June 25, 1971. Weed control evaluations were made June 25 and November 4, 1971. Location 2. A Kentucky bluegrass turf site was selected in Leisure World, Laguna Hills, California for a preemergence trial on smooth crabgrass. The herbicides were applied January 19, 1971, with a Namco Stainless Steel sprayer at 30 psi in 100 gpa. The plot size was 10 ft x 10 ft and was repli­ cated 4 times. The turf was spr,inkler irrigated after application to wash the herbicides from the foliage. Evaluations for pbytotoxicity were made February 23 and March 16, 1971. Weed control evaluations were made August 11, September 9, and October 27, 1971. Crabgrass infestation was not extensive or uniform throughout the trial. Location 3. Several herbicides were applied March 3, 1971, to a common bermudagrass turf in Reeding Park, Fresno, California. All treatments were applied with a Namco CO2 pressure sprayer at 30 psi in 50 gpa. The plots were 10 ft x 10 ft and replicated 4 times. The turf was sprinkler irrigated immediately after application. Sm~oth crabgrass (D. ischaemum) control and turf pbytotoxicity were evaluated June 1, 1971.- Location 4. Three trials were establist. ~d at the u.c. Davis campus. Trial 1 was a preemergence application like t11e other locations. Trial 2 was applied as an early postemergence, and trial 3 using combinations for post and preemergence. A redtop (Agrostis alba), bentgrass turf was used to evaluate several herbicides in these three t'rials. The three trials were applied February 2, March 8, and April 1, 1971, respectively. Each was applied with a Namco CO pressure sprayer at 30 psi in 108 gpa. Granular materials were applied ~y hand with a shaker canister. In trial 1 the 52 water was applied the following day for 30 min; trial 2 applied 4 hr after application for 30 min; and trial 3 applied the following day for 30 min {a~lowing 24 hr for foliage effect). The temperature at application was 55 F., 60-65°F., and 65-70°F. respectively for each of the trials.

In trial 1, phytotoxicity evaluations were made March 8, April 1, and June 4, 1971. Weed control evaluations were made June 4 and July 15, 1971. Trial 2 and 3 were evaluated June 3 and July 15, 1971. Results

Excellent preemergence crabgrass control was achieved with the herbi­ cides used as standards, DCPA, bensulide, benefin, and terbutol. Although NC 8438 gave good crabgrass control in Location 2, control was not good at the other locations. Phytotoxicity at 2 and 4 lb/A was observed on bluegrass, redtop, and bentgrass turf. Although injury was severe 2 weeks after appli­ cation, regrowth occured and was satisfactory 4 months after application. No injury was observed on bermudagrass turf at Location 3.

The herbicide CGA 10832 (CIBA-Geigy) gave good to excellent weed control at 3 of the 4 locations at 1, 2, and 4 lb/A. Only 4 lb/A gave good control of crabgrass at Location 4 {Davis).

Crabgrass control was not adequate at 1 lb/A of AN 56477 at all locations. Marginal control was achieved at all locations except Location 2 (Laguna Hills) with 2 lb/A. Control at this location was good at 2 lb/A. Four lb/A of AN 56477 was needed for good control in 3 of the 4 locations. Adequate tolerance was found on bluegrass, redtop, bentgrass, and bermudagrass turf in these trials.

The herbicide R 7465 gave excellent weed control at 0.5, 1, and 2 lb/A at Location 2. Weed control was adequate at only 2 lb/A in Location 1 and not adequate in the other trials. Phytotoxicity was observed at all rates at Location 1 on a bluegrass turf and at 2 lb/A at Location 4 on a redtop bent­ grass turf.

Good to excellent crabgrass control was achieved with oxidiazon in all trials at 2 and 4 lb/A. One lb/A was adequate to control crabgrass pre­ emergence in Location 3 and 4, however, not in Location 1. From the one evaluation after 9 months at Location 1, it would appear to give similar residual control as bensulide. The emulsifiable concentrate formulation used in these trials gave excessive turfgrass injury except on bermudagrass.

Oryzalin was applied in only one trial (Location 3) on bermudagrass turf. Crabgrass control was excellent at l, 2, and 4 lb/A, 3 months after application. No injury was observed at 3 months on bermudagrass in this trial; however, the Kentucky bluegrass present was severely injured at all rates.

Nitrofen at 2 and 4 lb/A did not give good weed control in 2 of the 3 locations applied. Good control was achieved only at Location 2. Since crabgrass population was low at this location, control evaluations might appear hi~her than from other locations. No phytotoxicity was observed at 2 or 4 lb/A on bluegrass, redtop, or bentgrass turf. 53

The herbicide pronamide was applied preemergence for crabgrass at. Location 3 only. Good control was not achieved at either 2 or 4 lb/A. Byzantine speedwell (Veronica buxbaumii) was controlled in this trial at 2 lb/A of pronamide. No injury was observed with pronamide on common bermuda­ grass turf at 2 or 4 lb/A. In the early postemergence crabgrass control trial at Davis, granular alachlor at 2, 4, or 6 lb/A did not control smooth crabgrass. The herbicide · A 820 gave control of smooth crabgrass for 88 days at 2, 4, or 6 lb/A; how­ ever, only 6 lb/A gave residual control to 132 days after application. Injury to the redtop and bentgrass was observed at the 4 and 6 lb/A rate of A 820 at 88 days. No injury was evident at 132 days after application. Of the three herbicides bensulide, benefin and DCPA, bensulide gave the best control at this "germinating" stage of growth. DCPA was probably less effective because of lower solubility and was not leached down to the germinat­ ing seed in sufficient concentrations to get control. Injury was quite pro­ nounced at 88 days on bentgrass with DCPA. In the trial using combinations of herbicides :for early postemergence and residual preemergence control, all treatments gave outstanding weed control without injury to the redtop and bentgrass turf. Table 1. Preemergence cr,bgrass control in turfgrass from four locations in·California.! Rate Location 1 Location 2 Location 3 Location 4 Herbicide Lb/A Formul. 6 25 11 4 8 11 10/27 6 1 6 4 7 15 DCPA 10 75 WP 9. 9. DCPA 15 10.0 10.0 9.0 berisulide 15 4 EC 10.0 9.0 10.0 10.0 10.0 10.0 9.9 benefin 3 1.5 EC 9.9 8.8 terbutol 15 80WP 10.0 10.0 NC 8438 2 18.2 WP 6.5 6.5 9.6 9.0 4.3 3.2 3.5 NC 8438 4 3.5 6.6 8.o 7.5 6.2 3.2 3.2 CGA 10832 1 4 EC 8.7 7.2 9.9 9.5 4.2 4.5 CGA 10832 2 8.7 6.2 9.7 9.0 9.0 6.8 5.8 CGA 10832 4 8.7 7.8 10.0 10.0 10.0 9.0 7.5 AN 56477 1 3 EC 7.5 7.5 8.9 7.8 3.5 3.2 AN 56477 2 8.5 6.o 9.5 8.9 8.1 6.5 5.8 AN 56477 4 10.0 5.8 9.3 8.1 10.0 7.8 7.0 R 7465 0.5 50 WP 4.o 4.o 9.5 8.1 6.o 2.5 R 7465 1 8.o 4.5 9.6 8.9 6.8 5.2 3.8 R 7465 2 10.0 6.o 9.9 9.6 7.5 5.2 3.5 oxidiazon 1 2 EC 8.2 6.2 9.0 9.5 9.5 oxidiazon 2 10.0 5.5 10.0 8.5 9.5 oxidiazon 4 9.7 6.o 10.0 10.0 oryzalin l 75 WP 10.0 oryzalin 2 9.5 oryzalin 4 - - - 10.0 nitrofen 2 50 WP 6.2 4.o 9·4 ~-6 3.5 1.5 nitrofen 4 7.5 4.2 9. .6 5.0 4.o pronamide 2 75 WP 5.0 pronamide 4 - 6.2 control o.o 3.2 7.8 7.5 o.o o.o 1.0 y crabgrass control: 0 = no effect; 10 = complete control 54

Table 2. Phytotoxicity from preemergen ~ crabgrass herbicides from four locations in California •.::! 1

Rate Location 1 Location 2 Location 3 Location 4 Herbicide Lb/A Formul. ?71½ 3723 6/25 2/23 3/16 3/3 4/16/4 DCPA 10 75 WP o.8 0.5 DCPA 15 0.5 o.4 (N) bensulide 15 4 EC o.o o.o o.o 1.0 0.5 (N) o.o o.o o.o benefin 3 1.5 EC 1.0 1.0 terbutol 15 80 WP o.8 0.5 NC 8438 2 18.2 WP 3.5 5.0 0.5 6.8 5.8 (N) 2.0 1.8 1.2 NC 8438 4 5.0 6.2 1.0 8.2 8.1 (N) 5.8 7.0 2.1 CGA 10832 1 4 EC o.o o.o o.o 0.5 1.1 0.3 o.o o.o CGA 10832 2 o.o 0.5 o.o o.8 o.4 (N) o.o o.o o.o CGA 10832 4 1.0 1.5 2.5 1.2 2.5 (N) o.8 0-3 0.5 AN 56477 1 3 EC o.o 0.5 o.o o.8 o.o 0.3 o.o o.o AN 56477 2 o.o o.o o.o o.8 0.9 (N) o.o o.o o.o AN 56477 4 o.o o.o 0.5 1.0 0.9 (N) o.o o.o o.8 R 7li65 0.5 50 WP 0.5 0.5 0.2 1.0 1.0 o.o o.o o.o R 7465 1 o.o o.o o.o 3.8 2.5 (N) 0.3 0.5 o.o R 7465 2 0.5 o.o o.o 5.2 4.7 (N) 2.3 o.8 0.2 oxidiazon 1 2 EC 2.5 0.5 o.o (N) 1.3 0.5 0.2 oxidiazon 2 5.5 1.8 0.5 (N) 2.0 0.5 1.2 oxidiazon 4 9.0 7.0 5.2 3.3 1.3 3.5 oryzalin 1 75 WP (N) oryzalin 2 (N) oryzalin 4 (N) nitrofen 2 50 WP 0.5 0.5 o.o 0.2 0.2 o.o o.o o.o nitrofen 4 0.5 o.o o.o 1.0 0.7 o.o o.o o.o pronamide 2 75 WP (N) pronamide 4 (N) control o.o o.o o.o (N) o.o o.o o.o

1/ phytotoxicity: 0 = no effect; 10 = dead turf (N) no phytotoxicity

Table 3. Early postemergence (at emergence) control of crabgrass and phytotoxicity to a redtop-bentgrass turf at Davis, California

Rate Crabgrass Control- PhY:totoxicity- Herbicide Lb/A Formul. 88 days 132 days 88 days 132 days alachlor 2 10% gran 4.2 2.8 0.2 o.o alachlor 4 2.8 1.0 0.5 o.o alachlor 6 5.5 2.0 o.8 o.o A 820 2 2.3% gran 8.2 6.1 0.2 o.o A 820 4 8.2 5.5 2.0 O.O A 820 6 8.8 8.2 2.7 O.O bensulide 15 4 lb/gal 10.0 9.9 0.3 O.O benefin 3 2-5% gran 8.5 8.8 1.0 O.O DCPA 15 75 WP 8.5 8.o 4.o o.o control 0.5 2.5 o.o o.o 1/ crabgrass control: 0 = no effect; 10 = complete control g/ phytotoxicity: O = no effect; 10 = dead turf 55 Table 4. Postemergence control of crabgrass in a redtop-bentgrass turf at Davis, California.

Rate Crabsrass Control- Herbicide Lb/A Formul. 88 days 132 days NO 8438 + 0.5 + 10 18.2WP + 10.0 8.o o.o o.o bensulide 4EC NC 8438 + 1 + 10 10.0 10.0 0.5 o.o bensulide MSMA + 4 + 10 4s + 4EC 10.0 9.6 o.o o.o bensulide nitrofen + 4 + 10 50WP + 9.2 8.o 0.5 o.o bensulide 4EC nitrofen + 8 + 10 10.0 8.8 o.8 o.o bensulide control 3.2 2.8 o.o o.o

1/ crabgrass control: 0 = no effect; 10 = complete control g/ phytotoxicity: 0 = no effect; 10 = dead turf

Tall fescue control in turfgrass. Johnson, E. J. and c. L. Elmore. Tall fescue is often planted at high seeding rates in low maintenance turf areas. However, when individual plants appear scattered throughout a blue­ grass, eye, or bent turf, they form large objectionable clumps. This can part"icularly be a problem in golf course fairways where the lay of the ball is important. Herbicides for non-selective control are available. The pur­ pose of this trial was to evaluate-2 materials for selective .control. On Februaey 18, 1971, two materials at 3 rates were applied and repli­ cated 4 times in a trial at the Burlingame Countey Club in San Mateo County. Terbutol 80 WP was applied at 10, 20, and 40 lb/A. Terbacil 80 WP was applied at 1/16, 1/8, and 1/4 lb/A. Plots were 5 ft x 10 ft and spray volume was 100 gal/A. Materials were applied with a stainless steel pressure sprayer connected to a uniform constant pressure source of co2 using 3 size 8004 Teejet nozzles. Results were negative. There was no phytotoxicity to tall fescue or to the desirable grasses in the turf.

Postemergence control of Eleusine tristachya in dichondrs. Elmore, c., R. Baskett, E. Roncoroni, and L. Smith. A severe stand of well established goosegrass was selected in a dichondra seed field near Clements, California, for testing of three postemergence herbicides and one preemergence herbicide. ':Che goosegrass was in the early flowering stage at the time of the first treatment on August 30, 1971. The trial area was irrigated the day before the herbicides were applied. All treatments were applied to an area 10 :rt x 20 ft with a knapsack sprayer with three 8004 Teejet nozzles in 100 gpa. The surfactant X-77 was added at the rate of 0.25% to all treatments except monu­ ron. Monuron was washed off of the dichondra foliage immediately after appli­ cation vhile the re~t of the herbicides were not irrigated for one week. The

------foliar herbicides were applied August 30 and September 20, 1971.

Evaluations of phytotoxicity to the dichondra and control of goosegrass were made September 13 and 20, October 12, and November 13, 1971 (Table 1). Control evaluations of hairy crabgrass and sprangletop were made September 20 and October 12, 1971 (Table 2).

Table 1. Effects of three postemergence herbicides and one preemergence herbicide on the control and phytotoxicity to dichondra.

Rate {lb/A) and Goosegrass Control* Dichondra PhytotoxicitY** Dates of Treat. Herbicide 8L3Q 9.L20 9/13 9/20 10/12 11l3 9Ll3 9l20 10L12 11L3 DSMA 4 4 4.7 5.3 5.6 5.6 1.0 0.7 1.3 1.3 DSMA 8 8 7.0 8.o 8.6 8.6 2.0 2.0 2.0 2.0 dalapon 4 4 1.7 2.3 3.6 6.o o.o 1.0 3.6 4.6 dalapon 8 8 2.7 4.o 5.3 6.6 1.3 2.3 5.6 7.6 MSMA 2 2 3.3 3.0 2.3 2.3 0.3 0.3 1.0 1.3 MSMA 4 4 5.8 5.7 6.3 8.o 1.3 1.3 1.6 1.3 monuron 2 1.3 0.7 o.o 0.3 2.3 1.7 0.3 1.0 control o.o o.o o.o 1.3 o.o o.o o.o 1.3

* weed control: 0 = no effect; 10 = complete control ** phytotoxicity: 0 = no effect; 10 = dead dichondra

Table 2. Hairy crabgrass and sprangletop control with three postemer­ gence herbicides and one preemergence herbicide in dichondra.

Rate {lb/A) and Hairy Crabgrass* SprangletoP* Dates of Treat. Herbicide 8/30 9/20 9/20 10/12 9/20 10/12 DSMA 4 4 7.0 5.6 o.o o.o DSMA 8 8 9.7 10.0 1.0 0.3 dalapon 4 4 3.7 8.o 9.5 10.0 dalapon 8 8 5.7 10.0 10.0 10.0 MSMA 2 2 9.0 8.3 0.3 o.o MSMA 4 4 9.0 10.0 1.0 0.3 monuron 2 2.0 o.o 7.7 o.o control o.o o.o o.o o.o

* weed control: 0 = no effect; 10 = complete control