Current Entom continuous study aims at and mites harmful

E. 0. Essig

The Division of Entomology and laboratory and field investigations. There Parasitology at Berkeley and Davis are over 200 -borne plant diseases aims at controlling the agricultural pests on record-many of which are exceed- of California, with special emphasis on ingly destructive to agricultural crops, those of importance to the northern part especially to truck and field crops, ber- of the state. ries, fruits, vegetables, and ornamentals. Red spiders and other mites infesting The studies involve the discovery of the agricultural crops are under constant insect vectors, the manner in which they study by nearly all staff members of the infect the plants, their distribution, life division. New miticides giving much bet- histories, and the most efficient means ter control than those previously known of their control. Typicol injury to young green tomotoer by the tomoto horn worm. are being used. Investigations are being carried out on mites infesting tomatoes, cucurbits and other truck and garden Fruits and Nuts crops; on alfalfa, clovers, barley and va- Studies are being conducted on all rious field crops; on cotton and potatoes. known pests affecting apples and pears, Mite studies on nuts, fruits and berries and the research work is being improved are directed particularly against red constantly through the development of spiders and blister mites in the coastal more effective insecticides and spraying and interior valley regions, and the cycla- and dusting equipment. Among the most men mite on strawberries. Mite research important insects involved are: codling on ornamental and on greenhouse plants moth, leafrollers and a great many other offers opportunities for first testing new caterpillars-old and new; , leaf- insecticides that might prove noninjuri- hoppers, bugs, scale insects, thrips, flat- ous to humans. Mites are being investi- headed and shot-hole borers, and mites. gated on stored food products of all Insects infesting stone fruits continue kinds, on poultry and on livestock. to receive special consideration. Many The navel orongeworm hor recently become a Insects as vectors of plant virus dis- new species have appeared in past years pert of walnuts in the trees ot ripening time and in rtoroge. eases are being studied in greenhouse, and others like the oriental peach moth are occasionally appearing. Special proj- Deformities of pears caused by lygus bugs and grassbugs when the fruit is small. ects cover all the common caterpillars like codling moth, bud moth, tortrix and other leafrollers, cankerworms, tus- sock moths and scale insects, aphids, thrips and mites. A number of the new insecticides and miticides show great promise. Progress is being made in the control and reduction of the fig and olive scales in the San Joaquin Valley. Grapes have received a great deal of intensive investigational work in connec- tion with the control of the grape leaf- hopper, leafhopper-vectors of Pierce’s Disease, grape leafroller, red s iders, grape bud and erinose mites, anlmany other pests. Nuts including almonds and especially walnuts are receiving much attention be- cause of severe insect and mite damage. On walnuts the developed control pro- grams on codling moth, Catalina cherry moth and others, the walnut and scale insects continues to be very success- ful. Red spider work is also progressing yearly. Continued on page 10

8 CALIFORNIA AGRICULTURE, AUGUST, 1951 ology Research Bscovery and control of all to agriculture in California

Robert 1. Metcalf

The Division of Entomology at River- results against black scale. Applications side and Los Angeles is responsible for sometimes produce abnormal population research on the control of insects which increases of soft brown scale, due to are of agricultural importance to more interference with the parasite-predator than 4,000,000 acres of cultivated land, complex. A new compound, S- ( 1,2-dicar- and which cause an estimated annual bethoxyethyl) 0,O-dimethyl dithiophos- damage of more than $100,000,000 to phate, has shown some promise in the southern California farm products. control of this soft scale. Additionally, co-operative research Many compounds of suitable boiling studies with the Division of Entomology Doints are beine tested as Dossible fumi- and Parasitology at Berkeley and Davis iants for CaliTornia red Iscale, yellow Type of damage to sweet corn done by the directly benefit the agricultural industry scale, black scale and citricola-. scale, and corn eamorm. a maior-- oest of sweet corn and of the entire state. for mites attacking citrus. To date no tomato. promising materials have been discov- ered. Citrus Pests Two new insecticides, DDD and ethyl Studies of mites attacking citrus re- p-nitrophenyl thionobenzenephosphon- sulted in the development of two new ate-EPN-300-have shown considerable acaricides which give excellent control of promise in the control of orangeworms the citrus red mite and are registered for and are being extensively used along with commercial usage. These are beta-chloro- parathion and cryolite in large-scale field ethyl-beta’- (p-tertiary-butylphenoxy ) -al- tests. pha’-methylenthyl sulfite-Aramite-and Several new organic phosphate com- p-chlorophenyl p-chlorobenzene sulfon- pounds such as a trialkyl thiophosphate- ate-Ovotran. Several other new mate- Systox-, dimethyl p-nitrophenyl thio- rials are showing promise under a variety phosphate, octamethyl pyrophosphora- of field conditions and in laboratory mide, and S- ( 1.2-dicarbethoxv-ethvl) 0,O-dimethyl dithiophosphat; shbw Tent caterpillars appear eorly in the spring studies. Aramite also controls the citrus and often defoliate deciduour fruit trees and na- bud mite. Continued on page 11 tive trees and shrubs. New materials are being tested for the control of citrus thrips. Aldrin and Growth retarding injury to young cotton plants caused by thrips. dieldrin look highly promising but have not yet been licensed for commercial usage because of lack of adequate infor- mation regarding possible deleterious residues, Studies of several other com- pounds indicate potential promise. Factors which may limit the usefulness of parathion in the commercial control of armored-red, yellow and purple-scales are being studied in field plots of more than 200 acres. Examined are post-treat- ment effects from commodity contamina- tion by parathion residues present in peel, pulp, juice and by-product oils, changes in fruit quality, possible toxic air contamination by parathion vapors in or near treated groves and interference with the biological control of various eco- nomic pests on citrus. A number of new insecticides are under investigation, but none has yet shown promise of attaining commercial usage. In control studies of unarmored scales of citrus, parathion, at economical dos- ages, has proved very satisfactory against citricola scale, and has given variable

CALIFORNIA AGRICULTURE, AUGUST, 1951 9 BERKELEY Truck crop insect investigations in- Other projects in this general field volve a great many crops and hundreds include studies of the biology and control Continued from page 8 of different kinds of insect pests such as of black gnats, mosquitoes, cattle grubs, As berries increase in acreage work on aphids, thrips, bugs, cutworms, army- and flies affecting man and . berry insects is being extended. Many worms, wireworms, leafminers, root mag- Studies in the identification, life his- years of intensive investigations have gots, stem maggots, and seed maggots, tories, distribution and control of plant been devoted to the study of the life his- crane flies, garden centipedes, snails and parasitic nematodes in California are tory and control of the cyclamen mite of slugs. Tests are being conducted in all well under way. Great strides are being strawberries. These investigations are be- parts of northern California and many made in the collection and indentification ing pressed with the hope of obtaining new discoveries in insect control have of these ultra-minute agricultural pests greater success with the newer miticides been made. The successful treatment' of and progress in control is being made. and perhaps also by such other means as seed to protect it from insect attack in the Supplementing the work of the Divi- resistant varieties and agricultural prac- soil is one of the really great contribu- sion has been the establishment of insect tices. The root borers, tree crickets, and tions in this field. Very many new insecti- collections at Berkeley and Davis with other insects and mites are also being cides are being tested constantly. This curators in charge. The collections now studied. work centers at Davis but nearly every number more than 1% million of speci- member of the staff is a part of the over- mens and many thousands of species. all project. Tomatoes, cucurbits, sweet- Forage Crops corn and a number of other crops have Alfalfa insect pests are being investi- special projects. Miscellaneous Projects gated closely, particularly for the control Countless numbers of insects, mites and of the alfalfa butterfly, lygus bugs, and other pests on the great variety and vol- other insects. Much has been done to es- Bees, Parasites ume of California ornamentals are being tablish a system of supervised insect con- Apiculture investigations include the studied. A special project has been set trol which is gradually being taken over building up of breeding stocks of Califor- up to cover this field as thoroughly as by the growers and which has resulted nia bees; studies of pollen grains gath- funds will permit. The testing of new in- in effective insect control and great sav- ered by bees; insecticides in relation to secticides upon these nonedible plants ings to alfalfa growers, especially in the beekeeping; the breeding and genetics of has been of great assistance to our field San Joaquin Valley. the honeybee including artificial insemi- investigators who are working on edible Continued studies are being made on nation; and the fundamentals of apicul- crops where residues are involved. the work and distribution of the alfalfa ture as related to agriculture in the state. Research of insecticidal residues on weevil. Many other insects of forage The control of insects and other para- food crops-fundamental to the use of crops are also included in these investi- sites of domestic animals is becoming an chemicals in insect control-aims at a gations. increasingly important goal of the Divi- better knowledge of the deposits, toxicity sion. At the present, active projects deal and analyses of toxic residues. Investiga- with studies in poultry parasitology; the tions involving taste and smell tests of Field and Truck Crops seasonal incidence of the parasitic nema- food products treated with insecticides or Cotton insects are being studied as new tode, Ostertagia circumcincta, of sheep, growing in treated soils are under way. insect and mite problems arise. At the the status and control of myiasis-produc- Miscellaneous investigations include present time effective control appears to ing flies in California; and control of the following: have been developed for lygus and plant livestock ectoparasites with hexachloro- 1, A survey and collection of all the bugs, aphids, mites and many other pests. cyclohexane and similar insecticides. insect species in California and the most important economic species in the West- The sugar beet leafhopper-A-eggs-C-and egg punctures-Lin the host ern States; 2, studies of all the aphids plant. The control of this insect is an important problem on the west side of the San or plant lice involved in the transmission Joaquin Valley. of plant virus diseases; 3, studies in the systematics and bionomics of native bees; 4, the life history, bionomics and systematics of the -true bugs; 5, morphology, biology and control of coleopterous insects injurious to forests and forest products; 6, investigations in insect physiology: respiration and ab- sorption and excretion; 7, researches on the and biology of North American Siphonaptera-fleas; 8, stu- dies of sawflies attacking trees and agri- cultural crops in California: taxonomy, biology and distribution of the Psyllidae -jumping plant lice; 9, the taxonomy, distribution and biology of California leafhoppers; and 10, the taxonomy, biol- ogy, ecology, distribution, and control of California species of thrips; 11, sys- tematic and economic studies of the gar- den centipedes which are injurious to agricultural crops and ornamentals. E. 0. Essig is Professor of Entomology, Uni- versity of California College of Agriculture, Berkeley.

10 CALIFORNIA AGRICULTURE, AUGUST, 1951