Number Of Insecticide Applications Research Articles

Comparison of a Cone Emergence Trap Procedure with the Monitoring of Tagged Nuts for Timing Insecticide Applications for Pecan Weevil (Coleoptera: Curculionidae) Control1

Potential was shown for the monitoring of tagged nuts for pecan weevil punctures. Minimal differences were observed in the number of nuts punctured and the number of insecticide applications made between the two sampling procedures. Advantages to the repeated monitoring of tagged nuts include the ability to assess pecan weevil damage and the infestation levels of other pecan insect pests such as the hickory shuckworm, Cydia caryana (Fitch), and the pecan nut casebearer, Acrobasis nuxvorella Neunzig, and diseases such as pecan scab, Cladosporium caryigenum (Ell. and Lang.) Gottwald. A major disadvantage to the monitoring of tagged nuts was the time required for tagging and subsequent sampling of the nuts through the pecan weevil season

Management of the Cabbage Looper and Diamondback Moth on Cabbage by Using Two Damage Thresholds and Five Insecticide Treatments124

The use of managemen decisions for controlling the cabbage looper, Trichoplusia ni (Hubner), and the diamondback moth, Plutella xylostella (L.), based on 2 thresholds of feeding damage, reduced numbers of insecticide applications compared to fixed schedules but resulted in a loss of marketable heads. A visual damage threshold of ≥ 1.0 feeding “window“/plant was advantageous over one of ≥ 1.0 hole/plant as it detected the presence of cabbage loopers in the early instars when they are more easily controlled. Permethrin tended to give better control than Bacillus thuringiensis var. kurstaki Berliner alone or in conjunction with methamidophos, and methomyl in this management program.

Photochemical reaction of chlorothalonil in organic solvents

Substantial residues (up to 40 ppm) of methyl parathion were extracted from clothing worn in a treated cotton field on the 1st day following application. Delaying re-entry until the 2nd or 4th day following application reduced residues by about 90 and 99%, respectively, as compared to the 1st day. The amount of residue accumulated on clothing increased as the growing season progressed and the number of insecticide applications increased. The areas of clothing covering legs and arms collected the highest amount of residue. Methyl parathion penetrated through an outer layer of fabric onto an under layer. However the residue level on the 2nd layer was only about 50% of that present on the 1st layer. Methyl parathion residues extracted from cotton fabric amounted to only 50–75% of that extracted from cotton-polyester (50/50). Washing was effective in removing 75–95% of methyl parathion residues from clothing. Washing clean fabrics with those containing methyl parathion residues resulted in contamination of the clean fabrics.

Effects of Tobacco Budworm Control at Different Treatment Levels with Several Insecticides on Flue-Cured Tobacco12

Control of Heliothis virescens (F.) at 3 different treatment levels (2.5, 5, and 10%) with Bacillus thuringiensis Berliner (Dipel®), methomyl, and monocrotophos maintained similar tobacco budworm infestations at the same treatment level on flue-cured tobacco for a given area where mid- to late-season infestations exceeded the 10% infestation level. Lower treatment levels maintained lower infestations of tobacco budworms. The number of insecticide applications required for tobacco budworrn control was influenced by the insecticide and treatment level used; the lower the treatment levels, the more applications required. No quality differences were apparent between the different treatment levels, but all significantly increased fluecured tobacco yields over untreated tobacco. The overall trend for the 3-yr study period was that the lower the treatment level designated, the greater the yield increase. However, under the conditions of these experiments in which the tobacco budworm infestations exceeded the 10% level at least once during each season, a 10% treatment level appeared most economical for Dipel and methomyl, but a 2.5% treatment level was considered economical for monocrotophos.

Pilot Insect Pest Management Program for Soybean in Southern Brazil1

During the 1974–75 soybean growing season, a pilot pest management program was tested in Southern Brazil. Nine paired field locations, varying in size from 10–30 ha, were selected in commercial farms for this experiment. One field of the pair was managed by following a simple pest management strategy and the other field by following farmers own criteria. The strategy consisted of scouting fields once a week to monitor populations of defoliating lepidopterous caterpillars and pod sucking stink bugs which were the target insect pests. Damage thresholds and treatment decisions were based on assessment of defoliation levels, pest populations, and presence of pathogens, mainly the fungus Nomuraea rileyi (Farlow) Samson. Minimal dosages of nonpersistent pesticides were prescribed in fields reaching damage thresholds. Although treatment decisions by farmers probably were influenced by the pest management program, they made a total of 9 treatments (avg one/field) as opposed to only 2 treatments made in the pest management fields, a reduction of 78% in the number of insecticide applications in the experimental program. The program was repeated in 1976 and was officially recommended by the state of Parana (2nd largest producer in Brazil). In 1977, a similar program was adopted on a national scale. The program allowed us to test under normal field conditions some parameters of soybean pest management systems developed in the United States. It demonstrated that simple scouting procedures and adequate economic damage thresholds can be used in preliminary pest management strategies even if phenology and population dynamics of key pests are incompletely known.

MODIFICATION AND FURTHER EVALUATION OF AN EQUATION FOR PREDICTING POPULATIONS OF CURCULIO CARYAE (COLEOPTERA: CURCULIONIDAE)

AbstractAn equation developed in 1972 and 1973 for predicting the number of adult pecan weevils, Curculio caryae (Horn), in pecan trees was modified to include natural survival and evaluated for estimating weevil population and for determining the initiation of control measures. This method of scheduling insecticide applications resulted in a lower infestation of pecan weevil than jarring, the most commonly used sampling method, with the same number of insecticide applications. The use of a prediction equation for estimating C. caryae populations to determine economic thresholds looks promising for the researcher, grower, or pest management specialist.

Minimum Number of Insecticide Applications for the Control of the European Corn Borer on Sweet Corn in Quebec1

Field experiments were conducted at St. Luc, Quebec, from 1963 to 1965, to determine the relative effectiveness of 1, 2, 3, or 4 applications of DDT or carbaryl (Sevin®) in 2 commercial sweet corn fields. In all cases, the 1st application was made 5 days after the beginning of egg laying period and the others at weekly intervals, except for the single application of DDT or carbaryl, which was made 15 days after the 1st eggs were observed. In general, results were similar for the 3 years: the early variety was more infested than the late variety, DDT was slightly superior to carbaryl, the peak of egg laying always occurred between the 2nd and 3rd insecticide applications, and the date on which the single application was made varied each year from only 2 to 4 days from the date of maximum oviposition. The results of this 3-year study indicate that under the conditions of heavy infestations of the European corn borer, Ostrinia nubilalis (Hubner), in southwestern Quebec, 3 applications of either DDT or carbaryl would be recommendable for an early variety of sweet corn and 1 application for a late variety to obtain economical commercial control.