The purpose of this study was to determine spider species composition and their temporal and vertical distributions in corn in southern Quebec. We sampled 30 corn plants weekly for 12 weeks from 9 July to 23 September in 1985. We found nine families, 14 genera, and 12 identifiable species. Web-building spiders were more abundant than hunting spiders. The dominant species was Tetragnatha laboriosa Hentz (Tetragnathidae). Web-builders were generally found under the ear of the plant, whereas the vertical distribution of hunting spiders was more even.

Mass trapping for control of the spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.), was evaluated during 1986 in one experimental orchard near Jordan Station, Ont., and in three commercial orchards in Norfolk County, Ont. Multi-Pher II® traps were used to trap adult males, and Vineland traps were used to monitor adult activity and to obtain a measure of the effect of mass trapping on adult male abundance. In the experimental orchard, Vineland trap catches were similar in the trapped and control plots. In two of the three commercial orchards Vineland trap catches were significantly smaller in the trapped plots during one of the three yearly activity periods. Pre-adult leafminer density was significantly lower in the trapped than in the control plots on three of the seven sample dates in the experimental orchard whereas in the commerical orchards, where up to 91 times as many adult males were trapped per plot per activity period, pre-adult density was significantly lower in the trapped plots only in one orchard on one sample date.

The taxonomy, distribution, life history, and host plant relationships of the cochylid moth Agapeta zoegana (L.), an oligophagous, facultatively multivoltine root feeder, are discussed. The results of oviposition and larval feeding tests with 56 plant species in five families are presented and show that A. zoegana is restricted to a few closely related species of Centaurea. In Europe the moth is widely distributed and abundant in the majority of the root-feeding guilds of Centaurea maculosa Monnet de la Marck studied, with densities of 23.6 larvae per 100 roots in eastern Austria/northwestern Hungary and less than 8 larvae per 100 roots in central Hungary and the Alsace. The acceptance of target North American species (the tetraploid form of C. maculosa and the diploid Centaurea diffusa Monnet de la Marck), the damage caused, and the active searching ability rate A. zoegana as a potentially effective natural enemy of spotted and diffuse knapweed in North America. Agapeta zoegana will be especially promising as it predominantly attacks the rosette, which is, according to a recently developed population model for diffuse knapweed in Canada, the most sensitive stage determining equilibrium knapweed density. Agapeta zoegana is compatible with Pelochrista medullana Staudinger (Lepidoptera: Cochylidae), another knapweed root feeder recently introduced into North America, and will complement the seed-feeding species already established. The moth was approved for release in Canada and the USA and has been established in British Columbia since 1984 on C. diffusa.

Induction and aversion-learning are two kinds of behavior modification that depend upon ingestion for their effect. Both have previously been demonstrated in laboratory experiments. The polyphagous, ground dwelling larvae of the arctiid Diacrisia virginica Fabr. have now been shown to experience these two kinds of behavior modification in the field under natural conditions. The adaptive value of aversion-learning is self-evident. The adaptive value of induction is obscure. Evidence is presented here showing that induction overcomes hierarchical specificity before the level of deprivation becomes critical. As a consequence, plants low in the hierarchy of acceptability become fully rather than marginally acceptable, thus minimizing interruptions in feeding. Interruption is known to engender deleterious physiological responses.

A simulation model was developed to predict the timing of European corn borer, Ostrinia nubilalis (Hbn.), larval mortality following exposure to Beauveria bassiana (Bals.) Vuillemin conidia. Model response was compared with laboratory and field data collected specifically for model validation. In laboratory validation experiments, four conidial doses of a B. bassiana isolate collected from the People’s Republic of China were applied to European corn borer larvae which were then incubated at fluctuating temperatures. Simulation results compared favorably with fungal development and mycosis under laboratory conditions. Field validation experiments showed that applications of B. bassiana to European corn borer neonates in whorl-stage corn resulted in mortality levels over 60% when conidia and European corn borers were placed on the plants on the same day. When B. bassiana conidia were placed on plants prior to European corn borers, mortality decreased linearly with time. Model predictions of the timing of European corn borer mortality were found to be accurate when B. bassiana conidia were placed on corn plants at the same time or prior to European corn borers. When European corn borers were placed on plants prior to conidia, the model underestimated the time to European corn borer death. Lack of model fit in this situation is thought to be due to delayed host and pathogen interactions on the corn plant rather than poor prediction of the physiological development of the disease.

Studies in eastern Ontario showed that the exotic parasite Dacnusa dryas (Nixon) typically has three generations a year that correspond seasonally to those of its host, the alfalfa blotch leafminer, Agromyza frontella (Rondani). The mature larvae of the third generation enter diapause in September and resume development in the spring. The egg – first instar interval, which occurs within the actively feeding leafminer, developed at rates similar to those of the host larva. The remaining two instars and the pupa, which occur within the host puparium, developed at rates similar to those of the host pupa; in the two non-diapausing generations, the durations of these stages decreased with rise in temperature from 13 to 23 °C. Coincidence of wasp flight and hatch of leafminer eggs was high in all three generations. This host–parasite synchrony results mainly from a sequence of three events during their life cycles: lack of development of the parasite beyond the first instar within the host larva, a temperature-dependent rate of development of the subsequent stages which is similar to that of the host pupa, and different overwintering strategies which result in the parasite emerging later than its host to sustain the relationship. Behavior of the parasite is described in relation to host detection, egg deposition, and reproduction.

The fecundity and sex ratio of progeny of Muscidifurax zaraptor Kogan and Legner were assessed on <1-day-old to >9-day-old Fannia canicularis (L.) pupae. Two age classes of parasites (1 day old and 2–3 days old) were used. Host age did not significantly affect production of progeny. Mean number of progeny per female increased in both parasite age groups on 3 successive days of host-exposure as the parasites aged: 4.5, 7.4, and 10.4 progeny per female were produced for the 1-day-old parasites and 7.6, 10.4, and 11.8 progeny per female were produced for the 2- to 3-day-old parasites. Sex ratio of progeny was not significantly affected by host age, averaging 77% females (range 63–92%). Mass rearing of F. canicularis on used M. domestica medium is described.

Daily rates of predation by Podisus maculiventris (Say) (Heteroptera: Pentatomidae) on Mexican bean beetle larvae, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), were measured in soybeans, Glycine max (L.). The number of Mexican bean beetle larvae attacked per predator per day remained consistently low throughout 2 years of study. Estimates of the area searched by P. maculiventris were calculated from the number of prey attacked, number of prey available for attack, and leaf area. As leaf area increased, P. maculiventris searched more area, demonstrating a search strategy shared with other predators of canopy-inhabiting prey in soybeans.

Two populations of Pissodes strobi (Peck), one from Sitka spruce, Picea sitchensis (Bong.) Carr, and the other from Engelmann spruce, Picea engelmannii Parry ex Engelm., were successfully induced to oviposit on the non-host lodgepole pine, Pinus contorta Dougl. var latifolia. The number of egg punctures excavated on the non-host was smaller than that on either Sitka or Engelmann spruce. Survival from egg to adult was similar on the non-host and the host trees. The two weevil populations differed in the degree to which lodgepole pine met the nutritional requirements for weevil development, as measured by weight of weevils and developmental time from egg to adult. In choice-feeding experiments, weevils reared in lodgepole pine rejected this species and chose Sitka spruce, suggesting that feeding preference in P. strobi is genetically fixed and therefore cannot be changed by rearing the insects on the non-host tree. The importance of these findings is discussed in relation to the idea of weevil control through the development of weevil-resistant varieties.

Annual catches of male spruce budworm (Choristoneura fumiferana [Clem.]) in sex pheromone traps over a 21-year period in northwestern Ontario were well correlated with larval population densities in each subsequent year (r2 = 81%). On the basis of the criterion of 3 successive years of increasing catches or a threshold of 50 moths per trap, warning of extensive defoliation could have been given 6 years in advance. In 18 plots in northwestern Ontario and 35 plots distributed throughout the province, coefficients of determination (r2) between catch and population density in the same generation ranged from 40 to 74% in 1982 and 1983, but fell below 23% in 1984 when population densities in many plots were high. Coefficients of determination between catch and population densities in the following generation (eggs or larvae) ranged from 41 to 62%. On the basis of several years of cooperative research, sex pheromone traps are now in operational use in eastern North America for monitoring spruce budworm populations.

Pinus pumila Regel growing at Takanegahara Plateau of Mt. Taisetsu, Hokkaido, Japan, were damaged by larvae of Cephalcia variegata Takeuchi and Gilpinia daisetusana Takeuchi. The feeding behavior and life history of C. variegata are reported.

Cystiphora sonchi (Bremi) females, fixed while ovipositing into leaves of perennial sowthistle (Sonchus arvensis L.), were sectioned and then examined with a light microscope. Sections revealed that this gall-inducing species oviposited into leaves of sowthistle via the stomatal openings of the lower epidermis. Furthermore, sections of eggs and surrounding leaf tissues indicated that the epidermis was not punctured during oviposition.

The oilseed rape crop, Brassica napus L. and B. campestris L., has undergone a significant chemical transformation during the last 15 years. Plant breeders produced cultivars with only trace levels of erucic acid in the oil compared with 40-50% in early cultivars, and with 18 μmol/g of glucosinolates or less in the oil-free meal compared with 62-1 15 μmol/g (Daun 1983). The new “Canola” cultivars were developed because erucic acid was a suspected health hazard for humans and glucosinolates caused the meal to be unpalatable or toxic to farm animals.