Esfenvalerate was sprayed on green pepper and pumpkin plants at 7.0 g (AI)/ha to control adult striped cucumber beetle, Acalymma vittatum (Fabricius), and spotted cucumber beetle, Diabrotica undecimpunctata howardi (Barber). Following spraying, residues of esfenvalerate on the two crops were determined and adult insects were swept and counted. Esfenvalerate was extracted using n-hexane from representative plant samples collected at different time intervals following spaying for residue analysis. Determination of residues using gas chromatography (GC-ECD) indicated initial deposits of 3.34 and 1.18 ppm on pumpkin and pepper leaves, respectively. Only trace levels were detected on pepper fruits on day 21 (0.0001 ppm). Half-life values were 1.11 and 2.79 d on pumpkin and pepper fruits, respectively, whereas the values were 1.92 and 3.38 d on pumpkin and pepper leaves, respectively. Periodic sweep-net collections from treated and untreated plots revealed mean beetle reductions of nearly 100% 1 h post-treatment and > 60% 2 wk after treatment on both crops. Results obtained may be useful for developing IPM strategies to reduce pesticide residues on produce.

Eight insecticides at two concentrations (low and high) were tested for toxicity to first, second, and third instars of Chrysoperla rufilabris (Burmeister). Lindane (0.65 and 1.3 g actual insecticide AI/l), endosulfan (0.375 and 0.75 g AI/l), carbaryl (1.2 and 2.4 g AI/l), azinphos-methyl (1.0 and 2.0 g AI/l, malathion (0.9 and 1.8 g AI/l), methomyl (0.225 and 0.45 g AI/l), phosmet (0.375 and 0.75 g AI/l), and esfenvalerate (0.0.15 and 0.03 g AI/l) treated cowpea aphids (Aphis craccivora Koch) were fed to the lacewing larvae in the laboratory. Among tested insecticides, azinphos-methyl was the most toxic insecticide to larvae at the low and high rates and was classified as moderately harmful. Lindane and carbaryl were slightly harmful; endosulfan, malathion, methomyl, phosmet, and esfenvalerate were harmless. In most cases the first instar larvae were the most susceptible to the insecticides tested. Both rates caused similar mortality of C. rufilabris larvae after 48 h of feeding with the exception of azinphos-methyl and methomyl which caused higher mortality at the high rate.

The midgut of adult southern pine beetles, Dendroctonus frontalis Zimmermann (Coleoptera: Scolytidae), contains digestive enzymes with optimal proteolytic activity in vitro near pH 7. General proteinase activity was significantly inhibited by serine and cysteine proteinase class inhibitors, while limited activation by cysteine proteinase class activators was apparent. These results indicate that both cysteine and serine proteinases are present in the adult midgut. The presence of both proteinase classes in adult southern pine beetles coincides with previous studies showing widespread occurrence of these two classes of proteinases as digestive enzymes in midguts of other coleopteran species, but represents one of few beetle species known to possess both proteinase classes simultaneously.

Spray table tests with cotton Gossypium hirsutum L. leaves demonstrated that petroleum oil/diluent residues caused higher mortality in laboratory susceptible tobacco budworm, Heliothis virescens L., larvae than in a laboratory resistant strain. Paraffinic diluents with bifenthrin caused higher mortality of the susceptible and resistant larvae under conditions of long-term exposure to spray residues than bifenthrin in an isoparaffinic oil or an aromatic solvent. None of the bifenthrin-oil treatments increased mortality above water-bifenthrin in either resistant or susceptible strains.

Field and greenhouse experiments were conducted to determine if organophosphate (OP)-resistant (R) and OP-susceptible (S) tobacco aphids exhibited tolerance or resistance to aldicarb, a carbamate insecticide. In the greenhouse, OP-R and OP-S aphids were placed in leaf cages on greenhouse-grown, flue-cured tobacco plants treated with various doses (0.0 to 1.0 g per plant) of aldicarb in the potting soil. Mortality was recorded after 24 h, and a dose-mortality relationship was examined. OP-S aphids were more susceptible as compared with OP-R aphids, to all doses of aldicarb. Leaf disks were collected on several dates from field-grown, flue-cured tobacco plants treated with 0, 11.2 or 22.4 kg per ha of aldicarb before transplanting. The leaf disks were taken to the laboratory, transferred to Petri dishes, and infested with ten OP-R or ten OP-S aphids. After 36 h, significantly higher mortality was observed in the OP-S aphids as compared with the OP-R aphids. These are the first test results to demonstrate a reduced susceptibility of OP-R tobacco aphids to aldicarb, a carbamate insecticide. The hypothesis that tobacco aphids with a chromosomal translocation are less susceptible to other types of insecticides is supported.

Adult azalea lace bugs survived the winters of 1990–91, 1991–92, and 1992–93 in central North Carolina. Females were capable of winter oviposition under both laboratory and field conditions. Two life-stages, egg and adult, commonly overwinter in North Carolina.

Electronic monitoring was combined with video observation in order to determine whether a characteristic body posture of the potato leafhopper, Empoasca fabae (Harris) (Homoptera: Cicadellidae), indicated probing. Styet probing was strongly correlated with (r > 0.99) and could be accurately predicted by a characteristic body posture. We describe a technique whereby video observation, alone, can be used to apply standardized pulses of leafhopper probing injury to plants.

Two types of pregelatinized corn flour were used to produce granules containing Bacillus thuringiensis Berliner subsp. kurstaki and various additives for control of the European corn borer, Ostrinia nubilalis (Hübner), in the whorl of corn plants. Laboratory-reared larvae were applied to corn whorls in the greenhouse and field, and a high natural infestation occurred at one field site (Champaign). In the greenhouse and at all three field sites, five of these formulations were just as effective as Dipel 10G, a commercially available B. thuringiensis product, for control of European corn borer larvae. In all greenhouse studies and at one of the three field sites (Champaign), the dose of B. thuringiensis could be reduced by as much as 75% when a phagostimulant was added to flour granules without significant loss of corn borer control. The phagostimulant dose response was not observed at the other two field sites in which larval infestations were relatively low. Flour type had no significant effect on European corn borer control under greenhouse and field conditions. Greenhouse evaluations provided results significantly similar to results from two of the field sites indicating the usefulness of the technique. The data presented highlight the versatility and potential for using novel formulation techniques for enhancing the efficacy of B. thuringiensis.

Results of a comparative analysis of the effects of seven different larval feeding regimes on the development of individually reared Chrysoperla rufilabris (Burmeister) larvae are presented. Also, four methods for presenting liquid artificial diet (capillary tubes, sponge, agarose based jelly, and artificial eggs) are discussed. Development time, pupal weight, fecundity, and reproductive rate were higher for C. rufilabris larvae reared on the eggs of either Helicoverpa zea (Boddie) or Sitotroga cerealella (Olivier) than for those reared on artificial diet. Diet presentation methods that show promise include agarose-based jelly and artificial eggs.

Emergence of hickory shuckworm, Cydia caryana (Fitch), adults from larval overwintering sites was bimodal. The major emergence peak occurred during the period of mid-March to mid-May and the smaller activity period during July and August. Pheromone trapping was effective for monitoring population trends during generations 1 and 5 of C. caryana but less so during generations 2, 3, and 4. Activity patterns suggest the species is crepuscular rather than truly nocturnal.

Insects, such as grasshoppers, Spodoptera spp. armyworms and flea beetles, occasionally defoliate seedlings of autumn-planted small grain crops. Seedlings of wheat, Triticum aestivum L., barley, Hordeum vulgare L., oats, Avena sativa L., rye, Secale cereale L., and triticale, X Triticosecale Wittmack, were mechanically clipped at the soil surface to simulate insect leaf injury for various periods after planting up to the 1-, 2-, and 4-leaf stages. Defoliation up to the 4-leaf stage (i.e., ≥ 30 days after planting) delayed spike emergence of all crops by several days. Seedling defoliation generally had little adverse effect on grain yield and test weight of rye in any year and reduced yield of triticale in one of three years. Furthermore, plants of both species defoliated in the 2- and 4-leaf stages were less severely damaged by cold temperatures and yielded as much or more than nondefoliated plants when late freezes occurred. Seedling defoliation up to the 4-leaf stage also had little negative effect on grain yield and test weight of wheat. Grain yield of barley and oats declined with increasing length of defoliation period in two of three seasons with most of the reduction occurring when defoliation exceeded 20 days. Results imply that seedling defoliation up to the 4-leaf stage has little effect on grain yield and test weight of winter wheat, rye, and triticale. Defoliation only adversely affected yield of barley and oats when it occurred beyond the 2-leaf stage. As long as plant stand is not reduced, economic thresholds for seedling pests of winter small-grain crops that do not allow for the loss of most leaf tissue for several weeks after planting probably are too conservative.

Ceralure, a new potent and persistent attractant for the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was evaluated in a new technique which serves as an alternative to aerial application of male annihilation bait-sprays for eradication. Residual ceralure and trimedlure contents, release rates, and medfly captures using panels coated with ceralure and trimedlure in stickem were evaluated for effective attraction of male medflies. The lure/stickem coated panels may be more effective than the Jackson trap baited with the “standard” trimedlure plug dispenser.

A specialized gypsy moth management program for urban parks was implemented in six state and county parks and the Beltsville Agricultural Research Center (BARC) in Maryland in 1990 and 1991. Decisions to treat with aerial applications of Bacillus thuringiensis Berliner (one or two applications) or diflubenzuron or to not treat were based on gypsy moth egg mass density, egg mass size, percentage of susceptible host trees, amount of previous defoliation, and the potential non-target effects of diflubenzuron. A total of 1025 and 1926 ha in the management program was treated with one and two applications of B. thuringiensis, respectively, and 1204 ha were left untreated. One block of 47 ha was treated with diflubenzuron. Larval mortality as a result of the treatments averaged 76 and 83% in areas treated with one and two applications of B. thuringiensis, respectively, and 87% in the area treated with diflubenzuron. Some noticeable defoliation occurred under all treatments. The greatest amount of defoliation (29% of total area) occurred in a management unit with an average initial egg mass density of 49,250/ha that was treated twice with B. thuringiensis. Comparisons with adjacent areas not included in the management program indicated that even when defoliation did occur, it was reduced both in severity and extent by the treatments. This evaluation of the gypsy moth management program that was developed to provide a high level of foliage protection in suburban parks indicated that a number of improvements can be made in the program. However, without more efficacious intervention tactics, the goal of preventing noticeable defoliation in any part of a management unit may not be achievable solely with biological agents where extremely high gypsy moth population densities are present.

Variations in size, weight, and lipid content of brood adult southern pine beetles, Dendroctonus frontalis Zimmermann, were investigated using a spectrophotometric technique to determine total lipid content of individual beetles. Large seasonal variations in these parameters were found with significant differences occurring between months and years. Patterns of variation, however, were not consistent with those reported in previous studies, leading to the conclusion that these variations do not have regular seasonal patterns. Variations in beetle measurements were not related to tree characteristics. Female beetles, on average, were heavier and contained more lipid than male beetles. The spectrophotometric technique used improves on a similar technique recently reported. The technique allowed more extensive measurements, including total lipid content, dry weight, and percent lipid content, to be taken on individual beetles.

Of four diets tested, one based on lima beans and casein was selected as the best and easiest for rearing third instars of Japanse beetles, Popillia japonica Newman. The diet gave the best survival and heaviest pupae and was previously used for rearing larvae of the New Zealand grass grub, Costelytra zealandica (White).

Root injury by western corn rootworm, Diabrotica virgifera virgifera LeConte, and northern corn rootworm, Diabrotica barberi Smith and Lawrence, larvae was evaluated in ten cornfields where adult densities had been monitored the previous August with cucurbitacin vial traps. Traps consisted of 60-ml perforated plastic vials containing an acetate strip coated with carbaryl and powdered squash with high levels of cucurbitacin, a feeding arrestant. Traps were attached to corn plants at ear height, and the beetles were collected and sexed at various intervals throughout the month of August. For all sampling intervals except the last week of August, female trap capture data explained a significant (P < 0.05) amount of variability in root injury the following summer. In contrast, the only case in which combined male and female trap capture explained a significant amount of variability was for the third week of August. However, even for this time interval, female trap data explained nearly twice as much variability as did total beetle capture. The best regression equations for predicting larval injury were based on mean female capture for the entire month of August (R² = 0.77, n = 9, P < 0.01), mean female capture for the last 3 wk of August (R² = 0.73, n = 10, P < 0.01), and mean female capture for the third week of August (R² = 0.82, n = 10, P < 0.001). This study underscores the need to develop a trap that captures only female corn rootworms.