Baldcypress, Taxodium distichum (L.) Richard, has been threatened recently by a new insect herbivore, the fruittree leafroller, Archips argyrospila (Walker) (Lepidoptera: Tortricidae). Baldcypress foliage varies from long-leaved, open-faced branchlets with leaves arranged in two-ranked fashion to short-leaved, appressed, imbricate branchlets. Field surveys revealed that the tallest trees contained 72 – 85% appressed foliage, whereas intermediate and small-sized trees contained 55–92% open type foliage. Over a three-year period, open morphology trees repeatedly exhibited significantly higher levels of defoliation (percentage of crown loss) by the fruittree leafroller, compared with appressed morphology trees. There was no ovipositional preference (number of egg masses) associated with morphology type. Differences in defoliation levels, therefore, were attributed to morphologically related influences on foliage suitability for larval stages.

The effect of parasitoid age and two instars of the host Helicoverpa zea (Boddie) were investigated for the endoparasitoid, Microplitis croceipes (Cresson). Third and fourth instars of H. zea were exposed to three different age ranges (3 to 5, 6 to 8, and 12 to 15-d-old) of mated adult female M. croceipes. No significant differences were shown in rate of parasitism regardless of parasitoid age or host instar. Significant differences (P < 0.05) were found between parental age and adult wasp emergence, sex ratio, and number in pupal stage entering diapause. Six to 8-day-old parasitoids parasitizing third instar hosts yielded the highest percentage of adult emergence (47.5 ± 14%; X̄ ± SD), the highest percentage of females (79%), and the lowest percentage (4.5 ± 6%; X̄ ± SD) entering diapause during the test.

Pupae of the Mexican fruit fly, Anastrepha ludens (Loew) (=mexfly), were placed outdoors at two localities in northeastern Mexico in order to measure mortality rates during this phase of the life cycle. Replicates were placed monthly in citrus orchards and in a montane canyon where native host plants supported wild mexfly populations. Replicates were placed in sheltered sites under trees and in exposed sites between trees. Adult flies emerged from 38% of these pupae. Deermice, Peromyscus leucopus (Rafinesque) and P. boylii (Baird), were found to destroy 34% of the total pupae. There was no difference in predation rates or adult eclosion between the orange grove and the montane canyon. There were significant (P = 0.05) differences in predation rates among months and in pupal survival between sheltered and exposed sites, with greatest survival of pupae in the sheltered sites during the summer months. Only weak correlations were found between monthly mortality rates and temperature and moisture extremes. The effects of weather variables were probably masked by the pattern of predation. In the native habitat variable predation rates seemed to result from natural cycles in the abundance of mice or from temporal shifts in their food supply. In the citrus orchard cultural practices such as irrigation and weed control displaced or reduced the rodent populations resulting in lower predation rates during some months.

A three-year study was conducted to assess the distribution and seasonal incidence of cereal leaf beetle, Oulema melanopus (L.), on wheat, Triticum aestivum L., in Tennessee. Cereal leaf beetle was distributed across the state with populations most frequently encountered in eastern and middle Tennessee. Cereal leaf beetle adults were active in wheat fields during late March to early April; eggs were found from late March to early May; and larvae were found from early April to early June, peaking during mid May. In our experimental plots, larval densities exceeded the suggested economic threshold during each year. F₁ adults emerged from late May to late June and fed approximately 2 wks on corn and other available Graminae plants. Adult activity then ceased; adults, eggs, and larvae were not encountered again until the following March and April.

Aqueous solutions of rubidium chloride, RbCl, (10 g/1, 10,000 ppm) were applied to foliage or soil of potted bell pepper and tomato. After 48 h, green peach aphid (Myzus persicae Sulzer) and potato aphid (Macrosiphum euphorbiae Thomas) were transferred to pepper and tomato, respectively. Leaf and aphid samples were collected after 6 d; remaining aphids were transferred to untreated plants. Aphid samples were collected periodically for 5 to 7 d. All samples were analyzed for Rb content. Results were similar for the pepper and tomato experiments. Soil-drench treatment produced significantly greater levels of Rb in leaf and initial aphid samples relative to foliar treatment. Levels of Rb in aphids from the two treatments were comparable after aphids fed on untreated plants for 24 h. Levels of Rb in aphids declined rapidly after removal from the source: undetectable by Day 6 in the potato experiment and reduced by nearly 90% by Day 5 in the tomato experiment. Foliar application of RbCl solution should be used in field situations. Application is more precise, and the length of detection is comparable with soil drench. Additionally, soil drenching with Rb produced an initially high peak of Rb in the aphids, which may have a physiological effect.

An epizootic caused by Furia virescens (Thaxter) Humber (Zygomycetes: Entomophthorales) was studied in a population of armyworms, Pseudaletia unipuncta (Haworth), in a tall fescue, Festuca arundinacea Schreber (Poaceae), pasture in Arkansas. Prevalence rates in live larvae collected from the field were 21.6, 8.1 and 13.5% for F. virescens, the braconid parasitoid Glyptapanteles militaris (Walsh), and an unidentified mermithid nematode, respectively. In a laboratory trial one Heliothis virescens (F.) larva was infected by F. virescens. Previously unrecorded aspects of the morphology and life cycle of F. virescens are described. Pseudaletia unipuncta and H. virescens are new host records for F. virescens.

Methyl palmitate and butyl palmitate, ant repellents first isolated from the sternal glands of paper wasps, were tested with a methyl ester homolog, methyl myristate, and Avon's Skin-So-Soft Bath Oil^© against foraging German yellowjackets. Repellency remained high for six days for all compounds except methyl palmitate. Avon's Skin-So-Soft^© was the most repellent. We suggest that this is due to two active ingredients, isopropyl palmitate and mineral oil.

Straw mulch reduced the number of Colorado potato beetle, Leptinotarsa decemlineata (Say), larvae on potato during the first generation, and reduced the proportion of stems that were more than 50% defoliated compared to unmulched and unirrigated control plots. Leaf mulch and trickle irrigation did not affect number of larvae or the proportion of heavily defoliated plants compared to the control. None of the treatments significantly affected the number of adults per stem until the end of the first generation and none affected the number of egg masses, so the straw mulch must affect mortality or development of eggs and larvae. Both types of mulch and trickle irrigation increased yield relative to the control, perhaps due to lower soil temperature in a hot, dry year.

Habitat preferences of generalist predators were evaluated by comparing their abundance among four reduced-tillage corn systems which differed in the degree of soil disturbance, quantity and structure of the surface mulch due to tillage, and cover crop management practices. Two sampling methods were used to collect predators, pitfall trapping and vacuum sampling. Although there was considerable difference in the composition of species collected with each method, similar trends in overall predator abundance were observed. Generalist predator abundance followed the gradient of ground cover. The treatment with the highest degree of mulch ground cover had the highest overall predator abundance while the treatment which was disked and without surface mulch had the lowest. Although most of the common species preferred those systems with the most ground cover, several species preferred the system with the least amount of ground cover.

Corythucha cydoniae (Fitch), the hawthorn lace bug, required an average of 55.6 – 18.5 days to complete development at temperatures ranging from 21 – 33°C. Nymphs emerged from eggs at 18°C but failed to develop further. Nymphal survival at 21°C was poor. Developmental thresholds for egg, nymphal, and total development were 13.3, 14.9, and 14.3°C, respectively. Thermal unit requirements for those stages were 162.9, 157.3, and 318.2 centigrade degree-days. Nymphal development was slightly accelerated by increasing the size of a cluster from one to three individuals at 24 but not at 27°C. Ovipositional rate was higher at 33 than 27°C, but total egg production was similar at both temperatures. Critical photoperiod for reproductive diapause was between 13:11 and 12:12 (L:D) at 24°C. Nymphal development was accelerated at short daylengths.

Three thrips species were commonly found in western Arkansas and northeast Oklahoma cowpea fields during the 1991 and 1992 growing seasons. These were the tobacco thrips, Frankliniella fusca (Hinds), the flower thrips, Frankliniella tritici (Fitch), and the soybean thrips, Sericothrips variabilis (Beach). Earlier planted cowpea fields in each area had higher thrips numbers than later planted fields. Tobacco thrips numbers tended to be higher during the early stages of the crop when the plants were small. As plants began to produce blooms, flower thrips numbers increased considerably. Peak flower thrips numbers typically occurred around two weeks after first bloom. Soybean thrips abundance was generally lower than the other common species and had no apparent pattern. Chirothrips crassus Hinds and Chirothrips spiniceps Hood also were found, but were uncommon.

A combination of fallow tillage and a March application of carbofuran were assessed as tactics for decreasing survival and reproduction of tobacco thrips overwintering in six harvested peanut fields. Large numbers of tobacco thrips, Frankliniella fusca (Hinds) (Thysanoptera: Thripidae), developed in three fields on volunteer peanut, Arachis hypogaea L., and winter annual weeds. Adult tobacco thrips collected during the late winter were predominantly brachypterous, with percent brachyptery averaging 71–95% for females. Brachypterous adults tended to be more abundant in fields harvested in September than in those harvested in October. Disking during November and February greatly reduced the density of volunteer peanut and winter annual weeds but did not measurably decrease abundance of brachypterous tobacco thrips. Carbofuran application reduced abundance of brachypterous adults and thrips larvae on volunteer peanut by 85–100% during the early spring. Post-harvest tillage and carbofuran application did not measurably reduce incidence of tomato spotted wilt virus in the subsequent peanut crop. Implications for winter ecology and management of spotted wilt are discussed.

Grape cultivars (Vitis) grown in northwestern Arkansas varied significantly in gall counts per leaf produced by the foliar grape phylloxera Daktulosphaira vitifoliae (Fitch). ‘Saturn’, ‘Fredonia’, ‘Campbells Early’, ‘Verdelet’, ‘Concord’, ‘Venus’, ‘Mars’, and ‘Cimarron’ had significantly fewer galls per leaf than did ‘Villard Noir’, ‘Himrod’, ‘Reliance’, and ‘Lakemont’. Gall counts significantly increased linearly as leaf width and hair density on the lower leaf surface decreased. Only grape cultivars with significantly larger gall counts per leaf had significant reductions in leaf widths relative to leaf widths on gall-free leaves. The relationship between leaf width and leaf hair density to grape cultivar susceptibility to foliar grape phylloxera is yet to be explained. A review of the mechanisms and suggested studies of leaf gall formation and prevention are presented.

Ultrasensitive acoustical equipment was used to detect larvae of the sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Curculionidae), in the sweet potato, Ipomoea batatas (L.). Methods of expressing results were evaluated with per cent audible as the best indicator of larval presence. Sound from moderately infested sweet potatoes (8 to 20 weevils/sweet potato) varied considerably even though infestation rates above 60 weevils/sweet potato resulted in sound throughout most of the observation period. Infested sweet potatoes were detectable after two weeks of weevil development; maximum values were observed a month after infestation. However, the substantial variation of the observation data precluded descriptive mathematical models based on infestation rate or weevil development. Disease processes also caused signals that were indistinguishable from those made by sweetpotato larvae. Other factors that influence detectability are also discussed.

True armyworms, Pseudaletia unipuncta (Haworth), were fed tall fescue leaves either infected or uninfected with the symbiotic fungus, Acremonium coenophialum Morgan-Jones and Gams. Young larvae fed endophyte-infected leaves weighed less than cohorts fed endophyte-free leaves, but developmental and survival rates were unaffected by endophyte infection. Older instar larvae fed endophyte-infected leaves weighed the same as those larvae fed endophyte-free leaves. Pupal weights also were unaffected by endophyte infection. These results were similar to recent studies conducted with other armyworm species and suggest that endophyte infection in tall fescue does not enhance resistance to a number of lepidopteran larvae.