65-1-33 Not For Publication

5240 December 1965

CONTROL OF SEED AND CONE IN A LONGLEAF SEED PRODUCTION AREA WITH A FIXED-PIPE SPRAYER--FIRST YEAR RESULTS

By

W. M. Ciesl~nd James L. Mcconnel#

INTRODUCTION

Seed and cone insects cause losses to seed crops of in the Southeast. Recent emphasis on reforestation with high quality seed has amplified this problem, particularly where seed production areas, set aside specifically to produce quantities of high quality pine seed, have produced only sporadic seed crops. A recent evaluation of losses due to seed and cone insects in the Brick Church Seed Production Area, a area located on the Witherbee District of the Francis Marion National Forest, South Carolina, indicated that extensive losses were being caused by the coneworm, clarioralis (Wlk.) (Ciesla and Franklin, 1964). Injury occurred primarily to first year cones in this area although larvae of this species damage both first and second year cones.

A pilot control project was initiated in 1965 to suppress coneworm infestations in this area. This pilot project was based on recent research on seed and cone control by Merkel (1964). A fixed-pipe insecticide sprayer system, similar to one developed by Grigsby (1964) was used to apply the spray. The purpose of this report is to describe operational and entomological phases of this project which occurred during 1965.

OPERATIONAL PHASES

The area involved in this project is a 55 acre long leaf pine stand, Pinus palustris Mill; located on the Francis Marion National Forest in the South Carolina coastal plain (Fig. 1). This stand is approximately thirty years old.

J/ Entomologist, Division of State and Private Forestry, Asheville, N. C. Y Tree Improvement Forester, South Carolina Seed Orchard, Witherbee, S. C. Fig. 1. Brick Church Seed Production Area, Francis Marion National Forest, South Carolina •

Fig. 2. Detail of pipe installation showing method of attaching pipe to tree, wooden block which prevents pipe slippage and grounding wire.

Fig • 3. Hose coupling connected to pipe.

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It was thinned to a density of about twenty trees per acre in 1963 and was set aside as a seed production area. Trees range in height from 65 to 78 feet.

A water emulsion of Lindane at a concentration of O. 5 percent gamma isomer was the chemical used. This was based on research by Merkel (1964) who reported that BHC at a concentration of O. 5 percent gamma isomer effectively protected slash pine cones from attack by Dioryctria sp. Lindane is essentially a refined form of BHC, containing only the gamma isomer, the only isomer of BHC which has insecticidal properties. This refined form was used because other isomers of BHC are also toxic to man and (Hayes, 1963) and were thus eliminated. The spray was formulated by mixing 2.5 gallons of 20 percent gamma Lindane emulsifiable concentrate with enough water to make 100 gallons of spray. A spreader-sticker (Pylac) was added to the original formulation at the rate of eight ounces per 100 gallons spray.

Three spray schedules were included as follows:

1. Mid-May, Mid-August

2. Mid-May, Mid-August, Mid-October

3. Late March, Mid-May, Mid-August, Mid-October

The sprayer system installation was not completed until April, therefore the March application in spray schedule three was not applied until mid-April. These spray schedules were directed primarily against Q. clarioralis and were decided upon after consultation with research personnel of the South­ eastern Forest Experiment Station V.

Three hundred trees were included in the pilot project. They were chosen by going through the area and selecting the trees which appeared to be good cone producers. Each tree selected was assigned a number. Trees were assigned to the various spray schedules from a table of random numbers. Seventy-five trees were included in each spray schedule and an additional seventy-five trees served as unsprayed checks. The sprayer system consisted of a one­ half inch galvanized pipe strapped to the bole of the tree with an irrigation sprinkler mounted about twelve inches above the crown. A Rain Bird Y No. 20A irrigation sprinkler was used. This is a rotating sprinkler with a one­ eighth inch nozzle and is the same sprinkler used by Grigsby (1964) •

.V Personnel communication, E. P. Merkel, S.E. F.E.S., Olustee, Florida .1/ Mention of commercial products does not imply endorsement by the USDA.

-4- Each sprayer system was assembled on the ground and was lifted into the tree with a block and tackle by ground workers. Trained tree climbers, using Swedish ladders fastened the pipe to the tree with pipe strapping. The strap­ ping can be adjusted as the diameter of the tree increases. A notched block of wood was nailed to the tree at the bottom of the pipe to prevent slippage (Fig. 2). Each pipe was grounded to protect the tree from lightning.

A Briggs and Stratton slip-on pump with a 240 gallon capacity tank and mounted on a stake-body truck was used to apply the spray (Fig. 4). A standard fire fighting nozzle with a "quick-release" coupling was used to connect the hose to the pipe. A faucet type valve was added to the coupling to facilitate controlled removal of excess liquid remaining in the pipe after spraying (Fig. 3). Excess liquid was collected to avoid spillage on the ground (Fig. S).

Approximately six gallons of spray were applied to each tree per application (Fig. 6). This required one and one-half minutes of actual spray time per tree at a pressure of 20 pounds P.S.I. at the pump. About forty trees could be sprayed with the 240 gallon capacity tank before refilling. No spraying was done when winds exceeded ten miles per hour. This generally permitted four-five hours of spraying per day. All trees in the three spray schedules could be sprayed during a one and one-half week period. A three man crew sprayed the trees, one operated the pump and two connected hose to the pipes. Crew members wore hard hats, safety goggles and rubber gloves while spray­ ing. Parts for sprayer systems cost $10. 78 per tree or $2,425.37 for the total area.

One major problem, yet unresolved, was the sprinkler head we used. The Rain Bird 20-A operates at an optimum pressure of about 25 pounds P. S. I. A large portion of the insecticide is sprayed beyond the crown of the tree and is lost at this pressure (Fig. 7). Pump pressures down to 20 pounds P. S. I. were tried to reduce diameter of throw of the sprinkler head but sprinklers did not rotate properly at these pressures. There was a considerable amount of variation among the sprinkler heads; some rotated rapidly, others slowly, often not making a complete rotation in one and one-half minutes.

ENTOMOLOGICAL PHASES

Evaluation of Sp@y Deposits -- Spray deposits were evaluated by adding a small quantity of a fluorescent dye (Leucophor C-6208 .s/ to the spray and checking foliage and branch samples under ultra-violet light. Laboratory tests showed that dilutions of up to one part Leucophor C per 1,000 parts water by volume fluoresce under ultraviolet light. This material was added at the rate of eight ounces per 100 gallons of spray. fl/ Manufactured by Sandoz, Inc., 61-63 Van Dam St., New York 13, N. Y. -s- Fig. 4. Slip-on unit mounted on stake body truck used to apply spray.

Fig. S . Collecting excess spray from pi pe after tree is sprayed.

Fig. 6 . Sprayer system applying spray to a seed tree.

Fig. 7. Sprayer system spraying beyond crown of a seed tree.

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Two types of ultraviolet lights were used. A Spectroline BLF-6 longwave ultraviolet handlamp §./ was used to check spray deposits on foliage and cone samples collected from sprayed trees by tree climbers. A Spectroline high intensity ultraviolet flood lamp, which projects a 175 foot beam, was used to spot check sprayed trees for spray distributions within crowns. These checks were made after dark.

Spray deposit checks made after the first spray period indicated that the spray was not adhering to the foliage and cones as well as desired. Fluorescence was obtained only from buds and needle sheaths both of which have relatively absorbent surfaces. We attempted to solve this problem immediately before the second spray application by substituting Natrosol for the conventional spreader-sticker. Na trosol is a hydroxyethyl ether of cellulose which in­ creases the surface tension and viscosity of water. This material has been used to reduce drifts of herbicide sprays applied by helicopter with consider­ able success (Suggitt and Winter, 1964). Mixtures the equivalent of one- i:mrth and one-half pounds of Natrosol 250HR per ten gallons of water were prepared in the laboratory and applied to potted Virginia pine seedlings and first-year long leaf pine cones. Deposits checked under ultraviolet light in­ dicated that Natrosol at the rate of one-hlrth pound per ten gallons spray would produce the desired degree of viscosity to insure adhesion to cones and foliage.

A field test of Natrosol was conducted on fifteen trees in the Brick Church Seed Production Area in early May 11. Cone and foliage samples taken from treated trees showed excellent deposits under ultraviolet light. Natrosol was substituted for the spreader-sticker for the remaining applications on the basis of this test. The Natrosol powder was premixed in a 55 gallon drum until the swelling reaction was completed.

Spray deposits, as checked by the high intensity ultraviolet flood lamp, were generally good following the addition of Natrosol. Missed areas could, in most cases, be attributed to sprinkler malfunction, usually the failure of the sprinkler to rotate properly. Spray deposits on the ground were generally restricted to within a radius of 15 feet of the bole.

Evaluation of Insect Populations -- The measurement of seed and cone insect populations in seed production areas presents some difficulties because seed trees are tall and cone samples are difficult to obtain. Several sampling schemes were tested during 1965 with varying degrees of success.

Y Manufactured by Blacklight Eastern, 24 Kinkel St., Westbury, N. Y. 11 Mr. C. J. Fox, Hercules Powder Company, Charlotte, N. C. provided technical assistance on this field test.

-8- One approach was to examine cones in selected permanent sample trees with a high power telescope. A Bausch and Lomb telescope with a 30X objective, mounted on a tripod was used to observe cones. Sample trees were photo­ graphed with a Speedgraphic 4 x 5 Press camera with a Polaroid film pack. Sample points were marked on the photographs and the number of injured and uninjured first and second year cones were tallied for each sample point. A total of thirty trees were examined in this manner. This method was dis­ continued after the second series of observations were made because new growth obscured sample cones and valid observations could not be made.

A survey was made with a hydraulic lift vehicle during July. A Mobile Aerial Towers "High Ranger•; provided by Power Equipment Company, Charlotte, North Carolina, was used. This unit had a working height of about 53 feet with booms fully extended. Twenty-one sample trees, representing all spray schedules and check trees were examined and approximately ten first year cones and ten second year cones were examined in each tree. All cones examined were numbered and marked for future observation.

The hydraulic lift vehicle proved to be an excellent device for making ob­ servations of this type. The results of the survey are presented in detail in an earlier report (Ciesla and Franklin, 1965). Briefly, they indicated that Dioryctria populations were relatively low in all treatments and the checks. The most striking observation made was a significantly higher in­ cidence of first year cone mortality in the check trees as compared to the sprayed trees. Approximately 70 percent of the first year cones on the check trees were killed as compared to 14 percent in the sprayed trees.

A second series of observations with the hydraulic lift vehicle was planned for late September. This set of observations had to be cancelled because the vehicle could not be made available at that time.

A final evaluation of the effectiveness of the chemical control was made in conjunction with the district's cone collection. All cones were collected from trees which had at least one bushel of cones. Proportion of cones in­ fested by Dioryctria was recorded for each tree as cones were collected and all Dioryctria infested cones were dissected in the laboratory to obtain an estimate of seed loss. Five apparently undamaged cones were collected from each tree. These cones were opened in the laboratory with a cone cut­ ter and the number of sound seeds and seeds damaged by seedworms, Laspeyresia spp. were recorded. This provided an estimate of losses due to these insects.

No differences in the incidence of Dioryctria infestation are apparent between sprayed and unsprayed trees. Levels of Dioryctria infestation ranged from 3. 6 to 5. 5 percent in all treatments; a relatively low level of infestation.

-9- Cone production on check trees was slightly higher than the sprayed trees (Table 1). Proportion of seeds destroyed per cone by Dioryctria attacks ranged from less than ten percent to 100 percent. Over half of the Dioryctria infestations resulted in a 100 percent seed loss (Table 2). Most of the cone­ worm infestation in second year cones was due to D. amatella {Hulst) (Fig. 8) .

The above data indicate that little or no reduction in Dioryctria damage oc­ curred as a result of the spray program. The spray schedules were directed primarily against l). clarioralis however, an insect which occurs more fre­ quently in first year cones. We could not evaluate insect populations in first year cones other than the time the hydraulic lift vehicle was available. The incidence of D. clarioralis attack was very low at this time. A better indication of the effectiveness of this spray program will be next year's cone crop.

Dioryctria populations were relatively low in both sprayed and check trees. It is possible that drifts may have reduced coneworm populations in the check trees. Spot checks of spray deposits with an ultraviolet light indicated that this was not the case but some drift, not measurable by the high intensity flood light, may have occurred. Coneworm population levels in the Brick Church Seed Production Area should be compared with coneworm population levels on a similar longleaf stand to eliminate this possibility in future evaluations.

A high incidence of infestation by seedworms, Laspeyresia spp. , was found in cones collected in this area (Fig. 9). Adult reared from cones which matured last year were identified as Laspeyresia ingens Heinrich 11 a com­ mon seedworm in long leaf pine (Ebel, 1963). An average of 66. 9 percent of the cones in all treatments contained Laspeyresia infestations. Up to five larvae were collected per cone and an estimated average seed loss of 12. 7 percent occurred as a result of infestation by this insect (Table 3).

There were no apparent differences in incidence of Laspeyresia infestations between sprayed and check trees. This was as anticipated since studies by Merkel (1964) indicate that BHC is not effective against Laspeyresia.

lV Det. D. Davis, Entomology Research Division, ARS, USDA, Washington, D. C.

-10- Fig. 8. Long leaf pine cone damaged by Dioryctria amatella.

Fig. 9. Long leaf pine cone with Laspeyresia inqens lazval galleries in cone axis.

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(9 Table 1. -- Cone production and incidence of Dioryctria infestation by treatments, Brick Church Seed Production Area, Francis Marion National Forest -- 1965

No. Trees Mean Cones Mean Dioryctria % Dioryctria Treatment: Sampled Collected/Tree Infested Cones/Tree Infestation

Check 16 140.5 5.1 3.6 .....I w Spray 27 126.2 7.0 5.5 I l 2 Sprays 15 115. 6 5.7 4.0

3 Sprays 23 116. 4 4.6 4 . 9 Table 2. -- Percent seed loss due to infestation by Dioryctria sp. Brick Church Seed Production Area, Francis Marion National Forest - - 1965

Percent Seed Damaged Number of Cones Examined Percent of Total

0-9 96 22.7

10-24 21 5.0 I

,I:>, -I 25-49 17 4 .0

50-74 17 4 .0

75-99 21 5.7

100 248 58.6

Total 420 100.0 RECOMMENDATIONS

The following recommendations are made to improve operational and evalu­ ational procedures relative to this control program in 1966.

1. The possibility of using a better sprinkler head should be investigated. Several sprinkler-head manufacturers have been contacted to determine if a product more applicable to this type of work is available.

2. Coneworm populations in the Brick Church Seed Production Area should be compared with populations in a similar longleaf pine stand some distance from the spray area to avoid the possibility of contamination of check trees.

3. A pilot test using O. 2 percent Guthion or Sevin should be incorporated into the spray program to reduce infestation by Laspeyresia. Application should be timed with adult emergence.

-15- Table 3. -- Level of Laspeyresia infestation by treatments, Brick Church Seed Production Area Francis Marion National Forest -- 1965

% Cones Mean Attacks Mean No. Seeds Mean Damaged % Seed Loss Treatment: Infested Per Cone Per Face Seeds Per Face by Lasi;2eyresia

Check. 61.1 1. 33 9.62 1. 18 12. 2 7

1 Spray 66.7 1. 30 10.17 1.27 12. 48 I

O") -I 2 Sprays 67. 5 1.54 10. 21 1. 75 17.20 3 Sprays 72 . 1 1. 63 9.64 1. 45 15.04

Total 66.9 1.48 9.81 1.25 12.74 (All treatments) REFERENCES

Ciesla, W. M. and R. T. Franklin. 1964. Evaluation of cone losses on the Brick Church Seed Production Area, Francis Marion National Forest, South Carolina. USDA Forest Service, Div. S &PF, Zone 1, FI&DC Office, Asheville, N. C. Rpt. 64-1-2.

Ciesla, W. M. and R. T. Franklin. 1965. A survey of seed and cone insects in a South Carolina seed p-oduction area using a hydraulic lift vehicle. USDA Forest Service, Div. S&PF, Zone 1, FI&DC Office, Asheville, N.C. Rpt. 65-1-23.

Ebel, Bernard H. 1963. Insects affecting seed production of slash and longleaf pines - their identification and biological annotation. USDA Forest Service. Southeast. For. Expt. Sta., Asheville, N. C. Research Paper SE-6.

Grigsby, Hoy C. 1964. Fixed-pipe insecticide sprayer protect cones of tall plus pines. Jour. Forestry 62 (10).

Hayes, Wayland J. 1963. Clinical handbook on economic poisons, emergency information for treating poisoning. U.S. Dept. Health, Education and Welfare, Public Health Services. CDC Atlanta, Georgia.

Merkel, Edward P. 1964 . Hydraulic spray application of insecticides for the control of slash pine seed and cone insects. USDA Forest Service, Southeast. For. Expt. Sta.,Asheville, N. C. Research Paper SE-9.

Suggitt, J. w. and J. E. F. Winter. 1964 . Minimum-drift viscous herbicide sprays for helicopter application to woody growth. Ontario Hydro Research Quarterly, Second Quarter.

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