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The role of adult nutrition in longevity, progeny production, and offspring sex ratio of Trichogramma minutum Riley was examined. On average, honey-fed females lived 26.4 days and produced 260 offspring; unfed females lived 3.5 days and produced 80 offspring. Feeding on fructose or sucrose also significantly increased longevity and fecundity over unfed females (fructose, 23 days and 230 offspring; sucrose, 21 days and 230 offspring) but to a lesser degree than feeding on pure honey. Females fed yeast suspension or water had no significant increases in longevity or fecundity compared to unfed females. Offspring sex ratios of long-lived females were male-biased (50–62% males), those of short-lived females were female-biased (74–82% females). Lifetime reproduction of honey-fed females was highest at 20–25 °C and relative humidities of 20–80%, but short-term offspring production (during the first 2 days after emergence) was highest at 30 °C and 60–80% RH. Females that had access to honey for only a 24-h period did not increase their offspring production over the first 4 days of their lives when compared to unfed females. The potential benefits of feeding adult T. minutum for mass-rearing and field release are discussed.

Trichogramma minutum Riley entered diapause, in the prepupal stage, in eggs of Lambdina fiscellaria fiscellaria Guenée held at 15°C, 12L:12D, but failed to do so in eggs of Ephestia kuehniella (Zeller), Sitotroga cerealella (Olivier), or Choristoneura fumiferana (Clemens) held under these conditions. The parasitoids emerged without diapause from eggs of all host species held at 25°C, 16L:8D, indicating a role of temperature or photoperiod, or both, in the diapause of the parasitoids in eggs of L. fiscellaria held at 15°C, 12L:12D. Percentage emergence of parasitoids from eggs of L. fiscellaria was virtually the same (>80%) after passing the winter outdoors or after approximately 3 months at 2 °C in the laboratory as it was when reared indoors in this host at 25°C, 16L:8D. Emergence of T. minutum was very poor (C. fumiferana, E. kuehniella, or S. cerealella. Apparently, T. minutum must parasitize diapause host eggs in order to enter diapause, and good survival after long-term low-temperature storage is possible only when T. minutum is in diapause. Trichogramma minutum will enter diapause in L. fiscellaria after 14 days at 15°C, 12L:12D, but the parasitoids need a period of storage at 2°C, 0L:24D for a high percentage of emergence to happen. Over 50% emergence was recorded for T. minutum, held for 300 days in eggs of L. fiscellaria.

The toxicity of the insecticides permethrin, azinphosmethyl, and methomyl to adult Pholetesor ornigis (Weed) and P. pedias Nixon was evaluated in laboratory bioassays. Older P. pedias (2 and 3 days old) were more susceptible than younger parasites (1 day old) to permethrin. Azinphosmethyl was slightly more toxic to female P. ornigis than to male P. ornigis or to P. pedias. There was no consistent difference in the response of adult P. ornigis compared with P. pedias exposed to permethrin or methomyl on treated paper disks. Methomyl was twice as toxic as either azinphosmethyl or permethrin. Male P. ornigis were less susceptible than female P. ornigis to permethrin, but the difference was significant in only one of four populations tested. Male P. ornigis were less susceptible than females to azinphosmethyl. In 1986, populations of P. ornigis which had been exposed previously to pyrethroid insecticides were less susceptible to permethrin than P. ornigis from orchards where pyrethroids had never been applied. The response of both Pholetesor spp. to permethrin varied significantly from 1986 to 1987.

The life stages of Phyllonorycter blancardella (Fabr.) were monitored in an orchard at Guelph, Ontario in 1981 and 1982 and the results showed discrepancies with the previous concept of a trivoltine species occurring throughout its range in eastern North America. Sleeve cages were used to monitor the development of the second, mid-summer generation of leaf miners in a low-maintenance orchard at Guelph in 1982 and 1984 and 2 commercial orchards at Simcoe, Ontario in 1984. The flight period of the first-generation adults occurred over approximately a 6-week period. From eggs laid early in the flight period, a large proportion of the larvae developed quickly and emerged to give a second-generation adult flight. As the flight period continued, there was an increase in the number of progeny whose development was delayed in the early instars. These larvae did not pupate until late fall and overwintered as pupae. Of the second-generation larvae, about 70–90% at Guelph and 35% at Simcoe had a delayed development (summer diapause) and formed a large proportion of the overwintering population.

The predaceous mite Balaustium putmani Smiley was studied in the laboratory and in apple orchards in southern Ontario. A rearing technique was devised which facilitated the study of the life history and behaviour of individual mites.Temperature and moisture influenced the development and hatching of eggs. In the presence of water, development proceeded more rapidly at the higher temperature of the 10°–25°C range tested. In the absence of water no development occurred. Larval B. putmani are free-living predators and although some were observed feeding periodically on pollen grains, they could not survive solely on this diet. All three motile stages are predators of a wide range of small, soft-bodied arthropods, but feed mainly on eriophyids and phytophagous tetranychid mites. The rate of consumption of the eggs and motile stages of the European red mite was determined for each motile stage at 20° and 25°C. Insemination is by externally deposited spermatophores and in the adult females, no facultative parthenogenesis was evident.

A rearing technique was developed to study various aspects of the biology of Zetzellia mali (Ewing) in the laboratory. The rate of development of Z. mali feeding upon the phytophagous mite Aculus schlechtendali (Nalepa) was determined at 9°±1°C and 14°±1°C (56% R.H.), 19°±1°C (33%, 56%, 76%, and 97% R.H.), and 24°±1°C (51% R.H.). The average preovipositional and ovipositional periods for 16 female Z. mali were 1.5 and 9.4 days respectively and an average of 1.7 eggs per day were laid by these females. Z. mali was found to be arrhenotokous with unmated females producing only male offspring and mated females producing 2.6 females: 1 male offspring. Diapause in Z. mali was broken at 24°±1°C, 16L:8D) with egg deposition beginning after 11 days (51% and 76% R.H.) or 12 days (33% and 96% R.H.) when the adults feed upon the winter eggs of Panonychus ulmi (Koch).A life table was constructed for Z. mali and the intrinsic rate of increase (rm) was determined to be 0.109 female offspring/female/day. The mean generation time (T) was calculated to be 21.0 days and the net reproductive rate (R0) during this time was 10.04. The theoretical stable age distribution of the laboratory population of Z. mali at 19°±1°C, 56% R.H. was 59% eggs, 15% larvae, 7% protonymphs, 6% deutonymphs, and 13% adults.Comparison of the intrinsic rates of increase and prey consumption of Z. mali and other species of predaceous mites indicate that Z. mali is not as efficient a regulating agent of phytophagous mites as the phytoseiids.

Degree-day relationships in the development of Lithocolletis blancardella (Fab.) and Apanteles ornigis Weed, its major parasite, were established from laboratory and field studies in Ontario apple orchards during 1973, 1974, and 1975. Under constant laboratory conditions, temperature thresholds for development of overwintering pupae were estimated by three methods, and found to be 6.3°, 6.7°, and 5.7°C for L. blancardella, and 10.4°, 10.4°, and 11.3°C for A. ornigis. Degree-day accumulations in the field were calculated by two methods using daily maximum and minimum temperatures recorded from the pupal habitat and a Stevenson screen. Degree-days in the pupal habitat accumulated from 1 January, above 5.7°C for L. blancardella and 11.3°C for A. ornigis were more accurate than Stevenson screen degree-day accumulations for predicting first emergence; however, after emergence, seasonal development was best related to Stevenson screen degree-days accumulated from 1 April, above 6.7°C for L. blancardella and 10.4°C for A. ornigis. This study shows that degree-day relationships can be used in an apple pest management programme to optimize timing of insecticide applications against L. blancardella and preserve A. ornigis, its major natural enemy.

Populations of two abundant coccinellid species, Coleomegilla maculata lengi Timberlake and Hippodamia tredecimpunctata tibialis Say, responded rapidly to corn leaf aphid populations [Rhopalosiphum maidis (Fitch)] once the aphids became exposed to predation when the plants tasselled. Coleomegilla m. lengi oviposited at lower densities of aphids than did H. t. tibialis but H. t. tibialis was shown to have a greater numerical response than C. m. lengi at high densities of aphids due to its greater fecundity. The numerical response of the coccinellids by oviposition was linear with a lag of 1/2 week behind the aphid population.

Adult flies of the apple maggot, Rhagoletis pomonella (Walsh), were monitored for 6 years at Guelph, Ontario using aerial and ground-emergence traps. Two degree-day (°D) models to predict adult emergence were tested. Fifty percent of the adults were captured in an average of 809 ± 50 (SD) °D8.7 and first capture was at 638 ± 60°D6.4. Degree-day models which have been proposed previously and those developed in this study were only slightly more accurate than average calendar date for predicting adult emergence. Differences in °D requirements for emergence in each year were correlated with the length of cold period and the correlation suggested that the length of cold period preceding morphogenesis affects either the number of °D required to complete postdiapause development or the threshold temperature for development.

Low temperature is a major factor regulating diapause development inHolcothorax testaceipesRatzeburg. Diapausing pupae required a cold period of 0°C, 5°C, or outdoor (≤0°C) for ca. 15 weeks to terminate diapause. The pupae required a further 21–27 days at 21°C for 50% emergence. Longer periods and higher temperatures of storage often were associated with shorter times of morphogenesis and duration of emergence. Percentage emergence ofH.testaceipeswas constant after various periods of cold storage at low temperatures. After storage at 0°C, pupae held at 21°C and a 16-h photophase reached 50% emergence sooner than those held at the same temperature but at a 12-h photophase. Photoperiod did not affect percentage or duration of emergence of the parasitoid. The threshold temperature for development of pupalH.testaceipeswas estimated to be 9°C regardless of sex or host species. The thermal constant did not vary with sex of the parasitoids but differed significantly forH.testaceipesreared onPhyllonorycter ringoniellaMatsumura (237 DD) and onPhyllonorycter blancardella(F.) (202 DD). Temperatures from 11 to 29°C did not affect percentage and duration of emergence from overwintered pupae, which were 75.5% and 2.4 days respectively, when reared onP.ringoniella, and 86.2% and 1.7 days respectively, onP.blancardella. These results suggest thatH.testaceipesacceptsP.blancardellaas a host and will be synchronized with its development in Ontario.

Application of granulosis virus (CPGV) to plots of apple trees reduced deep-entry damage to apples by the codling moth, Cydia pomonella (L.), compared with nontreated apples. However, shallow-entry damage to apples by codling moth was as great, or greater, in virus-treated plots than in nontreated plots. Protection was improved by applying CPGV at least three times during each of the two annual generations of the codling moth compared with less frequent application.Bioassays showed that activity of deposits of CPGV on apples in the field was reduced to approximately 50% of original activity within 2 days after application and to 17% by the 10th day.