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Three mark–recapture experiments were conducted to determine patterns of movement in the Colorado potato beetle, Leptinotarsa decemlineata (Say), over an agricultural landscape in Maryland. In the 1st experiment, beetles were released from a central point and recaptured 5–20 d afterward in potato trap fields extending outward in 4 compass directions to a maximum distance of 0.65 km. Approximately 30% of released beetles were recaptured. Recaptures declined rapidly with distance, and a few beetles were recaptured 0.65 km from the release point after 5 d. A stream and a dense winter cover crop may have acted as impediments to movement over part of the experimental area. In the 2nd and 3rd experiments, beetles were released at various distances in 4 compass directions from a central “trap” field and recaptured 5 d later. Recapture rates were = 20% when beetles were released at 50 and 100 m and 6.5% when released at 300 m. Direction of release was a significant variable in the recapture rate in one of these experiments but not in the other. The results suggest that effective field rotation to reduce beetle population densities from year to year will require a distance of ≥0.5 km.

Lycoriella mali (Fitch) populations were exposed to mushroom compost that contained mushroom mycelium growth of various ages to determine whether the suitability of the compost for fly development was affected. It was found that unspawned compost was infested by flies and other invertebrate pests and that the more the compost was colonized by mushroom mycelium, the fewer the L. mali produced. The reduction in flies was greatest after 12 days of mycelium growth. The type of compost apparently affected its suitability for fly development. Also, freshly made compost was less suitable for L. mali than aged compost. Large numbers of mites and nematodes were associated with fly infestations. This demonstration of the vulnerability of uncolonized mushroom compost to invertebrate pest attack could explain the variation in pest populations among different mushroom-growing facilities.

The role of leptine glycoalkaloids in resistance to Leptinotarsa decemlineata (Say) was studied with Solanum chacoense Bitt. clones that had been selected for extremes of leptine level. Three high-leptine (120–306 mg/100 g fresh weight) clones, one from each of three accessions, were compared with three low-leptine (0–51 mg/100 g) sib-clones for number of adults and feeding damage in the field, adult feeding rate on leaf disks, and larval development on detached foliage. Number of adults per plant on the six clones ranged from 1.5 for the clone with the highest leptine level (306 mg/100 g) to 37.5 for a clone lacking even a trace of these rare glycoalkaloids. There were also wide and significant differences among the six clones for adult feeding damage, adult feeding on leaf disks, larval development rate on detached foliage, and survival to adult eclosion. Differences between the high- and low-leptine clone from each accession were significant for all five resistance parameters, and these differences appeared to be directly related to the concentration of foliar leptines.

The fragrant chemical compound volatilized by the bladder flower, Araujia sericofera Brot., was identified as phenylacetaldehyde. It attracted many economically important species of moths, and when it was used with a blacklight trap, it increased trap collections of pest moth species by 48%.

Blacklight traps were operated for 43 months at a density of 3 per square mile on an isolated tropical island, St. Croix, U. S. Virgin Islands, to determine the effect on populations of 25 insect species. Subsequently, the density of traps was reduced to 0.3 per square mile for 18 months, and changes in the collections were noted. The test species were: Agrius cingulatus (F.), Callionima ramsdeni (Clark), Eumorpha vitis (L.), Hyles lineata (F.), Manduca rustica harterti (Rothschild), Manduca sexta (L.), Xylophanes pluto (F.), X. tersa (L.), Heliothis virescens (F.), H. zea (Boddie), Ecpantheria icasia (Cramer), Gryllus assimilis (F.), Microcentrum triangulatum Brunner, Neoconocephalus triops (L.), Schistocerca pallens (Thunberg), Acrosternum marginatum (Palisot De Beauvois), Loxa pilipes Horvath, Nezara viridula (L.), Jadera rufofusca Barber, Bothynus cuniculus (F.), Phyllophaga microphylla Moser, P. portoricensis (Smyth), Calosoma alternans alternans (F.), Conoderus sp. and Lacon subcostatus (Candeze). Many species had decreased populations as measured by BL trap collections during the 43 months, and within a year after the trap density was reduced most had surges to population levels as high or higher than those recorded during masstrapping. Lepidopteran population indices were more affected than indices of other orders. Generally, most decreases and increases in populations appeared to be related to the trapping, but the numbers of some species that were removed by the traps were so low that any effect was indirect. Blacklight traps have a potential as a supplement for other control measures or possibly as a control themselves if the trap area is sufficiently large or sufficiently isolated.

The potential bacterial mutagenicity of the beta-exotoxin of Bacillus thuringiensis var. thuringiensis was detennined by the Salmollella-microsomal assay (Ames test) and found to be nonmutagenic. The activity of three experimental preparations of B. thuringiensis var. thuringiensis were determined by feeding the preparations to house fly larvae and to neonateColorado potato beetle larvae, Leplinotarsa decemlineala (Say). Comparisons with controls were made as to food consumption and mortality rates, and the LDIOthrough LDQ, were calculated. In field tests of 0.05-ha plots of potatoes, an experimental preparation of B. lhuringiensis var. lhurillgiellsis provided excellent control of the Colorado potato beetle when applied weekly at the rate of 1,892 ml/O.4 ha.

Ethanol extracts of the glandular hairs, leaves, or fruit of the tomato plant were found to contain materials repellent to the adult female and the immature forms of Tetranychus urticae Koch and T. cinnabarinus (Boisduval), but not to the adult males of these species, nor to the adult females of T. turkestani Ugarov and Nikolski. The repellent had a half-life of ca. 1.7 h.

This study was designed to determine how the preference of an insect for a plant line is affected by the proximity of less or more attractive lines. The test insects and their host crops were the potato leafhopper, Empoasca fabae (Harris), on potatoes; the imported cabbageworm, Pieris rapae (L.), on cabbage; and the Mexican bean beetle, Epilachna varivestis Mulsant, on lima beans. Comparisons were made between infestations in previously reported resistant and susceptible crop cultivars or lines. Field plots were planted all in a resistant cultivar or line, all in a susceptible cultivar or line, or the two cultivars or lines intermixed. The plant array did not have a significant effect on the size of the Mexican bean beetle population in the resistant or susceptible cultivars. A mixed planting of cultivars preferred and nonpreferred by the imported cabbageworm accentuated the differences between the two cultivars, although an unknown character of the preferred cultivar reduced the differences. Nonpreference was more apparent in isolated pure stands of potato lines than when the preferred and nonpreferred lines were in the same plot.

Collections of male tobacco horn worms, Manduca sexta (L.), in blacklight (BL) traps can be increased 10 or more times by baiting the traps with virgin female moths (Hoffman et al. 1966, Cantelo and Smith 1971). However. the rearing of these females is expensive and time consuming, and a synthetic female pheromone is not available. Therefore, we hoped to find a substitute material that could be used to increase collections. Isoamyl salicylate was chosen for evaluation because when it was used to bait relatively inefficient screen traps in Tennessee, it caught as many as 925 tobacco hornworms in a season. Also, 16 other species of sphingids were caught, but only Byles lineata (F.) and Xylophanes tersa (L.) were caught “in numbers” (Morgan and Lyon 1928). Moreover, at Oxford, N. C., collections in 12 similar-type traps (Stahl 1954) baited with isoamyl salicylate plus simulated jimson weed flowers averaged 112 M. sexta and 155 tomato hornworms, M. quinquemaculata (Haworth), each year from 1942 through 1953 with peak yearly collections of 414 M. sexta and 218 M. quinquemaculata . (However, in 1949, unbaited BL traps collected 15 × as many hornworm moths (both species) and in 1952–53 7–9× as many as the baited screen traps.)