Insecticide Programs Research Articles

Impact of a Methyl Parathion Spray Program on the Alfalfa Weevil 1 Parasite, Bathyplectes curculionis2 , in Pennsylvania 3

A 4-yr study determined the impact of methyl parathion, as commonly used against the alfalfa weevil, on the alfalfa weevil parasite Bathyplectes curculionis in Pennsylvania. The 1st generation of B. curculionis each spring coincided with the peak alfalfa weevil larval population and produced the greatest number of parasitized larvae. Each year the insecticide treatment significantly reduced the number of immature and adult parasites. The parasite-host ratio also declined relative to that in the unsprayed area. One week after spraying, each year, the numbers of immature parasites were reduced 93.2–100%. This reduction over the total period between spray and harvest ranged between 84.6 and 95.3%. In addition, the number of nonparasitized host weevil larvae also declined to near undetectable levels, consequently, reducing the oviposition potential for any adult parasites surviving in the sprayed area. The number of parasite larvae in the methyl parathion area declined significantly during the 3-yr spray program. During the 4th yr, when no spray was applied, B. curculionis larval populations increased in both the sprayed and unsprayed areas. However, the population in the sprayed area remained significantly lower than that in the unsprayed area indicating that B. curculionis populations did not fully recover following 3 yr of insecticide stress. The reduction in parasite numbers during this study was accompanied by a 9x increase in the weevil larval population. It is apparent that alfalfa weevil management schemes which do not judiciously integrate insecticide programs with B. curculionis biology can greatly reduce this parasite's potential.

Apple, Summer Mite Control, 1978

Abstract Test materials were applied to apple trees at Monomouth, Maine, as dilute sprays with a hand gun from a hydraulic sprayer operating at 300 psi. In Test 1, 28-yr-old trees were sprayed at a rate of ca. 250 gal/acre; in Tests 2 and 3, 13-yr-old apple trees were treated at 500 to 600 gal/acre. Spray dates were Jun 23 and Jul 3 (Test 1), Jun 26 and Jul 3 (Test 2), and Jul 20 and Aug 16 (Test 3); each material was applied on both dates for the respective tests. The fungicide and insecticide program during the course of these acaricide tests consisted of captan 80W (1.25 lb/100 ga I) on 4 dates; Imidan 50W (1.25 lb/100 gal) on Jul 5, 17, and Aug 2; Thiodan 50W (.5 lb/100 gal) on Jul 11 and 17; and Sevin 80W (1.25 lb/100 gal) on August 15. There were no tank-mixtures of acaricides with other pesticides. There were 4 single-tree replications per treatment. A randomized, complete-block design was utilized with 2 Golden Delicious and 2 Red Delicious cultivars per treatment in Tests 1 and 3 and 2 Cortland and 2 Mcintosh per treatment in Test 2. From each tree, 25 leaves were collected mostly at chest-height around the periphery of the tree, brought into the laboratory, and brushed onto glass plates coated with a Tween 20-alcohol mixture; mites were counted the same day. Mite population pressure was heavy in August. On the prespray date, egg populations ranged from 4 to 8 eggs/leaf (Test 1), 1 to 2 eggs/leaf (Test 2), or 15 to 30 eggs/leaf (Test 3). July and August were very dry and hot months.

Considerations for the Use of Pyrethroid Insecticides for Deciduous Fruit Pest Control in the U.S.A. 1

Rationale are presented for the careful introduction of pyrethroid insecticides into decidous fruit pest control programs and more specifically apple IPM systems. Factors emphasized are the cost-benefits of current IPM programs, the stabilization of resistance development among pests and the adaptation to chemical stresses of several beneficial natural enemy species relative to currently used, organophosphorus-based insecticide programs.

Influence of Spray Programs on Seasonal Abundance of Pecan Leaf Scorch Mite and Phytoseiids in Louisiana1

The population dynamics of Eotetranychus hicoriae (McGregor) were studied from May to Oct. in 3 managed and one abandoned pecan orchard in northern Louisiana during 1975 and 1976. The seasonal abundance of the pecan leaf scorch mite (PLSM) varied in each managed orchard primarily as a result of the insecticide programs followed. In the abandoned orchard, the PLSM exhibited low populations through midseason and eventually reached peak levels in late Aug. Insecticides were shown to be detrimental to the phytoseiid populations and appear to be partially responsible for the larger PLSM populations found in the managed orchards.

Apple, Summer Mite Control, 1977

Abstract Test materials were applied to apple trees at Monmouth, Maine, as dilute sprays with a hand gun from a hydraulic sprayer operating at 300 psi. In Test, 27-year-old trees were sprayed at a rate of ca. 300 gal per acre; in Tests 1 and 3, 12-year-old trees were treated at 500 gal per acre. Spray dates were June 23 and 30 (Test 1), July 1 and 8 (Test 2), and July 18 and 27 (Test 3); each material was applied on both dates for the respective tests. In addition, Omite 6EC at 2 oz, Omite 30W at 5 oz, and Plictran 50W at 1 oz were also applied on July 11 and 26 (Test 1). The fungicide and insecticide program during the course of these acaricide tests consisted of captan 80W (1 .0 - 1.25 lb/100 gal) on 5 dates, Epsom salts (15 lb) and Marlate 50W (3 lb) on June 16, and Sevin 80W (1.25 lb) on June 29, July 13, 28, and August 18. There were no tank-mixtures of acaricides with other pesticides. There were 4 single-tree replications per treatment. A randomized complete block design was utilized with 2 Golden Delicious (GD) and 2 Early Mcintosh cultivars per treatment in Test 1, 2 GD and 2 Red Delicious (RD) per treatment in Test 2, and 4 RD per treatment in Test 3. Twenty-five leaves were collected mostly at chest-height around the periphery of each tree, brought into the laboratory, and brushed onto glass plates coated with a Tween 20-alcohol mixture; mites were counted the same day. Mite population pressure was very severe. On the prespray date, egg populations ranged from 3-8 eggs/leaf (Test 1), 45-60 eggs/leaf (Test 2), or 15-30 eggs/leaf (Test 3). July was a very dry month.

Apple, Integrated Test, 1977

Abstract Several insecticide programs were evaluated for insect control, mite suppression, and influence on the predators, Stethoruspunctum and Hyaliodesvitripennis. Sprays were applied to 2-tree plots in a randomized block design with each plot consisting of a York and a Golden Delicious tree. Each treatment was replicated 3 times. Treated plots were separated by others not sprayed with insecticides. Treatments were applied as 6X concentrates with a Friend Airmaster 393 sprayer at 25 gpa/alternate side spray driven at 2 mph, except for Ambush 2EC which was applied at 50 gpq/complete spray. Spray dates for the insecticide treatments were: May 3, 12, 20 & 27, June 4, 13, 20 & 27, July 5, 12, 19 & 26, Aug 2, 9, 16 & 24. The Ambush 2EC compound was applied: May 3 & 20, June 4 & 20, July 5 & 19, Aug 2 & 16. The 2 treatments of SD 43775 2.4EC were applied: May 2, 13 & 23, June 4, 14 & 24, July 5, 15 & 26, Aug 5, 15 & 25. Penncap M compound was increased to 177 ml/A and Cygon 25W was dropped on July 5. On July 29, 85 g Plictran 50W/25 gpa was applied to all treatments. Fungicides applied during the season were: Cyprex, Polyram, sulfur, captan and zineb. Avg. temperatures were: May 63.88°F, June 66.23°F, July 74.34°F and Aug 72.67°F. Rainfall in inches averaged: May 0.88, June 2.91, July 5.73, and Aug 2.57. Effectiveness on the apple aphid was evaluated by counting the number of infested terminals/10 terminals/tree, the number of aphid infested leaves/terminals, and the number of aphids/most infested leaf/infested terminals.

POPULATIONS OF SOME MAJOR PESTS AND THEIR NATURAL ENEMIES ON YOUNG AND SEMIDWARF APPLE TREES IN NOVA SCOTIA

AbstractThe population densities of several major apple pests and their natural enemies were studied in an insecticide-free young bearing orchard and in an older orchard of semidwarf trees on an integrated control program. In mature orchards of standard size trees, greater natural mortality occurs than that reported in this study. Over a 5-year period most pests, with notable exceptions, increased rapidly under insecticide-free conditions whereas occasional numerical surges of certain pest species occurred under the mild insecticide program. Insect damage on fruit at harvest averaged 24% in the insecticide-free orchard and 8% in the integrated control orchard which had 2.4 times more harvested fruit.

Apple, Summer Mite Control, 1976

Abstract Test materials were applied to apple trees at Monmouth, Maine, as dilute sprays with a hand gun from a hydraulic sprayer operating at 300 psi. In Test 1, 26-year-old trees were sprayed at a rate of ca 250 gal per acre; in Tests 2, 3, and 4, 11-year-old apple trees were treated at 500 gal per acre. Spray dates were June 22 and 29 (Test 1), July 7 and 14 (Test 2), July 23 and August 2 (Test 3), and July 29 and August 5 (Test 4); each material was applied on both dates for the respective tests. The fungicide and insecticide program during the course of these acaricide tests consisted of captan 80W (0.6 - 1.25 lb/100 gal) on 6 dates, Epsom salts (15 lb) and Marlate 50W (3 lb) on June 24, Sevin 80W (1.25 lb) on July 8, 22, August 6 and 12, and Polyram 80W (1 lb) and Cygon 2.67EC (1.5 pt) on July 26 and August 5. There were no tank-mixtures of acaricides with other pesticides. There were 4 single-tree replications per treatment. A randomized complete block design was utilized with 1 Red Delicious (RD) and 3 Golden Delicious (GD) cultivars per treatment in Test 1, 4 RD per treatment in Test 2, 2 Cortland and 2 Early Mcintosh per treatment in Test 3, and 2 Mcintosh and 2 GD per treatment in Test 4 . From each tree, 25 leaves were collected mostly at chest-height around the periphery of the tree, brought into the laboratory, and brushed onto glass plates coated with a Tween 20-alcohol mixture; mites were counted the same day. Mite population pressure was not very severe. At the pre-spray date, egg populations ranged from 2-13 eggs/leaf (Tests 1 and 2) or from 20-35 eggs/leaf (Tests 3 and 4). There was abundant rainfall from mid-June through mid-August.

Pear, Pear Psylla Seasonal Control, 1976

Abstract Seven seasonal insecticide programs were applied with a Myers speed sprayer to 2 pear blocks containing Bartlett, Bosc, Gorham, and Clapp Favorite cultivars. Each program except that evaluating MO 9087 which was replicated only once, was replicated 3 times. All plots were ca 1 acre and arranged in a randomized complete block design. Sprays were applied on March 29, April 9, April 29, May 24, June 30, July 20 and August 9. All were dilute (IX) except the petal fall spray on May 24 which was applied 3X. Nymphs were sampled on May 17, June 29, and July 26 by putting 10 spurs from each of 4 trees/replication into a Berlese funnel. Adults were sampled by searching for 2 minutes on 4 trees in each plot on August 9 before the final spray application.

Apple, P. Ulmi Summer Control, 1975

Abstract Test materials were applied to apple trees at Monmouth, Maine, as dilute sprays with a hand gun from a hydraulic sprayer operating at 250-300 psi. In Test 1, 25-year-old trees were sprayed at a rate of 250 gallons per acre; in Tests 2 and 3, 10-year-old trees were treated at 500 gallons per acre. Spray dates were July 10 and 18 (Tests 1 and 2) and July 28 and August 5 (Test 3); each material was applied on both dates. The fungicide and insecticide program during the course of these acaricide tests consisted of captan 80W (1 lb), Thiodan 50W (0.5 lb) and lead arsenate (2 lb/100 gal) on July 17, and Thylate 65W (1 lb) and Sevin 80W (1.25 lb/100 gal) on July 30. There were no tank-mixtures of acaricides with other pesticides. There were 4 single-tree replications per treat-ment. A randomized complete block design was utilized with 1 Red Delicious (RD) and 3 Golden Delicious (GD) cultivars per treatment in Test I; 1 Cortland (C) and 3 RD per treatment in Test 2; and 1 Early Mcintosh, 1 RD, 1 GD, and 1 C per treatment in Test 3. From each tree, 25 leaves were collected mostly at chest-height around the periphery of the tree, brought into the laboratory, and brushed onto glass plates coated with a Tween 20-alcohol mixture; mites were counted the same day. Mite population pressure was very severe. At the prespray date egg populations ranged from 20-35 eggs/leaf (Tests 1 and 2) or from 40-80 eggs/leaf (Test 3). Late July and August were hot and dry.

Seasonal Abundance of Heliothis larvae on Cotton in the Presidio, Texas, Area12

Both the bollworm, Heliothis zea (Boddie), and the tobacco budworm, H. virescens (F.), are very important pests of cotton in the Presidio, Tex., area. Infestation levels often require an extensive insecticidal spray program over most of the cotton produced in the area.

Spread of the Boll Weevil 1 into the High Plains of Texas 2

In recent years Anthonomus grandis Boheman has invaded the High Plains, where it currently presents a potential threat to cotton in most of the area. A large-scale insecticidal control program was conducted during each of the years 1964–70 to control the insect. The programs were effective in preventing economic boll weevil damage to cotton in the High Plains. Despite these control efforts, low numbers of the insect advanced many miles west into previously uninfested counties of the High Plains during 1967–69. Distribution of the insect during 1964–70 in the High Plains and adjacent areas of West Texas is presented.

Effect of Nitrogen Fertilization on the Abundance of Cotton Insects1

Tests were conducted from 1964-1966 to determine the effect of different rates of nitrogen side dress applications on the abundance of and damage from cotton insects in nonirrigated cotton under a seasonal insecticidal control program. Insect infestation or damage counts were made on the boll weevil, Anthonomus grandis Boheman; bollworm, Heliothis zea (Boddie); and the cotton aphid, Aphis gossypii Glover. The insecticidal spray programs resulted in effective control of boll weevil and bollworm during each of the 3 years. Significant differences in boll weevil square infestation caused by the different treatments of nitrogen were obtained only 1 year. Significant differences in bollworm damage to bolls did not occur among treatments with nitrogen during any of the 3 years. Although there was an indication that more aphids occurred on leaves as the rate of nitrogen was increased, significant differences among treatments were obtained only 1 year. The effects of nitrogen side dress applications on the yield of seed cotton per acre were inconsistent.

A Comparison of Season-Long Cotton-Pest-Control Programs in California During 19661

Five season-long insecticidal control programs were compared for their impact on pest and beneficial insects in a 240-acre cotton field. The pest species encountered were Lygus Hesperus Knight; the cabbage looper, Trichoplusia ni (Hubner); and the bollworm, Heliothis zea (Boddie). The beneficial insects assessed were a minute pirate bug, Orius tristicolor (White); a big-eyed bug, Gcoeoris pallnes Stal; a collops beetle, Gollops vittatus (Say); a damsel bug, Nabis americoferus Carayon; and a green lacewing, Chrysopa carnea Stephens. L. hespems was suppressed most effectively by 5 applications of toxaphene-malathion, 4 applications of Bidrin® (3-hydroxy- N, N -dimethyl- cis -crotonamide dimethyl phosphate), and 5 applications of toxaphene-DDT, All chemicals were applied when an average of 2 or more L. hesperus per 50 net sweeps was encountered. In another toxaphene-DDT program, 3 treatments applied each time an average of 10 L. hesperus per 50 net sweeps was found resulted in moderate reduction of this species. The abundance of L. hesperus in the control exceeded the recommended treatment level of 10 bugs per 50 net sweeps in 7 out of 13 weekly samples taken from June 6 to August 30. During the period of L. hesperus control, predator abundance was severely reduced in the toxaphene-malathion and the 2 Bidrin programs. It was moderately reduced where 5 applications of toxaphene-DDT were made and less severely so in the limited toxaphene-DDT program (3 applications). In August, an outbreak of cabbage looper occurred in all the chemical programs. By contrast, the control which had retained its predator populations suffered the lowest infestation and the least damage. One of the Bidrin programs was not treated and was extensively defoliated by cabbage looper. The other Bidrin program was treated at weekly intervals with Bacillus thuringiensis Berliner and was not seriously damaged. Two applications of toxaphene-DDT gave the most effective chemical control of cabbage looper. In late August and September, bollworm was significantly reduced in the programs receiving I and 3 applications of toxaphene-DDT, but unaffected by 3 applications of toxaphene-carbaryl and 4 of B. thuringiensis . The Bidrin program, which had been heavily defoliated by cabbage looper, was not treated for bollworm, yet the bollworm infestation remained below that found in the control. Four evaluations of boll set made during the season at periodic intervals showed no significant differences between any of the chemical programs and the control. However, in the final boll count made following the period of bollworm infestation the degree of bollworm damage was lowest in the 2 toxaphene-DDT programs followed by the Bidrin program, which had not been treated for bollworm. Correspondingly, at harvest, the highest yields were produced in the 2 toxaphene-DDT programs followed by the latter Bidrin program. But, only the toxaphene-DDT program which had received the least number of applications produced a significantly greater amount of cotton than the control.

Integration of the heliothis nuclear polyhedrosis virus into a biological control program on cotton.

A biological control program for Heliothis species on cotton consisting of the naturally occurring predator-parasite complex and the nuclear polyhedrosis virus was integrated into a cotton-insect-biological-control program. Heliothis control with biological agents was compared with a toxaphene-DDT-methyl parathion control program using 25–30 acre plots. The virus was applied at 1.2×1011(20 I.U), 30×1011(50 I.U), and 6.0×1011(100 I.U) polyhedral inclusion bodics (PIBs) per acre. The initiation of virus applications was varied to evaluate the effectiveness of the virus against various ages of larvae, The Heliothis biological control program compared favorably with the insecticide program when virus application was initiated to coincide with hatch of high egg populations.

Distribution of Cyclodiene-Insecticide Resistance in the Seed Maggot Complex in Relation to Cropping Practices in Southwestern Ontario1

A survey conducted at 29 locations in southwestern Ontario indicated that seed maggots ( Hylemya platura (Meigen): H. liturala (Meigen) complex) have become generally resistant to cyclodiene insecticides. The percentage of resistant individuals varied considerably in relation to type of farming and the resulting insecticide program. In corn and pasture areas 76% of the population remained susceptible, 62% in crucifer-growing areas, 27% in vegetable-growing areas, and 22% in tobacco-growing areas. Both H. plalura and H. lilurata were resistant in the tobacco-growing area of Norfolk and Elgin Counties. The results are discussed in relation to residues of cyclodiene insecticides in soil, soil type, and the possibility of extended movement of adults. The practical implications of the work also are discussed.

Progress on Insecticidal Control of Apple Insects

Studies were conducted from 1959 through 1962 toward developing additional insecticidal spray programs to supplement or replace the standard lead arsenate-DDT program for apple insect pest control in Wisconsin orchards. Based on results from previous studies, Guthion® ( O,O dimethyl S- (4-oxo-1,2,3-benzotriazin-3 ( 4 H) -ylmethyl phosphorodithioate), carbaryl, and diazinon were used as basic materials in new programs for comparison with the standard for seasonal control of insect pests and for quality and flavor of the harvested fruit. Where high populations occurred, dieldrin was added to each of the new programs and TDE to the carbaryl and diazinon programs for plum curculio, Conotrachelus nenuphar (Herbst); and red-banded leaf roller, Argyrotaenia velutinana (Walker), control, respectively. Effectiveness of the spray programs was increased by adequate coverage and timing of applications to coincide with the appearance of major pests. Costs were minimized by reducing dosage rates between generations. All programs were used successfully during the 4-year study to produce apples of high quality and flavor which were usually 95% to 98% free of insect injury at harvest. The Guthion, diazinon, standard, and carbaryl spray programs were the most effective, in that order, for total insect control. The results were substantiated by a continuation of the study through 1964.

Development of Populations of the Boll Weevil in Fields Treated with Various Insecticides During 1959, 1960, and 19611

Seasonal populations of boll weevils, Anthonomus grandis Boheman, were carefully sampled in a number of small cont iguous cotton fields where control programs with different inticides were being conducted. Records were also made of cotton fruiting and fruit damage by weevils in these fields and in untreated control areas to determine the relationships between boll weevil numbers, abundance of fruit, and boll weevil damage, as well as the effectiveness of the insecticidal programs. The organophosphorus compounds were generally more effective for the control of overwintered weevils than the other types of insecticides used, but continued emergence of boll weevils after squaring began during 1960 and 1961 reduced the effectiveness of programs depending on a single application for the control of overwintered weevils. Continuously high populations in the untreated areas resulted in greatly reduced boll set, but the emergence of large numbers of weevils in the treated fields which increased square damage temporarily did not reduce boll set. However, in the treated areas higher percentages of punctured Squares were usually followed by higher percentages of weevil damaged bolls. The rate of population increase from generation to generation and the amount of damage caused by each weevil depended to a great extent on the numbers of squares on the cotton and the intensity of competition for those squares. In untreated fields during 1960 and 1961 first generation increases over overwintered populations were about S-fold and 2-fold respectively.

Sequential Plans for Sampling Aphids on Sugar Beets in Kern County, California

An efficient sampling plan, to aid in the timing of treatments, is essential to the development of a practical insecticidal program for possible, use in the control of Myzus persicae (Sulzer), the major vector of the beet yellows viruses. Sequential sampling, in which decisions are made upon the accumulated results of each unit sampled, in many eases can save both time and money. Although the tendency of aphids to colonize individual plants leads to what is known as over-dispersed, or contagious, distributions, critical population levels (assumed to be approximately one aphid per plant) are reached before 100% of the plants are infested. This fact permits the use of sequential sampling plans based upon either the mean number of aphids per plant or the number of plants found to be infested. In situations of very light or very heavy populations the use of a sequential sampling plan should allow rapid decisions to be made as to whether critical population levels have been reached.

Field Experiments on Control of Overwintered Boll Weevils

Field experiments at Florence, S. C. (1956-1959) strongly indicated the value of an insecticidal control program that started just prior to the formation of the first squares on the cotton plant and was directed primarily at the over wintered boll weevil ( Anthonomus grandis Boh.). Early insecticide application programs conducted prior to July 1 were nearly as effective as the same programs with additional later sprays when the infestation reached 10%. In 1958 the 10% level was not reached for 5 and in 1959 for 4 weeks after the early program was discontinued. There was some tendency for bollworm buildups when the early program was practiced.