Laboratory tests indicated that phorate, phorate sulfoxide, and phorate sulfone were toxic contact insecticides with broad spectrum activity. In general, p. sulfoxide was most toxic to insects > p. sulfone > phorate. When compared with other insecticides using 24–48 h old field crickets, Acheta pennsylvanicus (Burmeister), as test insects, the three compounds were less toxic by direct contact than carbofuran and fensulfothion, but as or more toxic than aldrin. P. sulfoxide and p. sulfone were strongly inactivated in moist Plainfield sand and were not as insecticidally active in soil against crickets as phorate. Nevertheless, the sulfoxide arid sulfone in soil were intermediate in toxicity between carbofuran and fensulfothion. The insecticidal activity of phorate, p. sulfoxide, and p. sulfone in soil was influenced by soil type, moisture, and temperature. Fumigant toxicity tests indicated that the three compounds volatilized from soil. Chemical analysis showed p. sulfone was most persistent in sand and muck > p, sulfoxide > phorate. Oxidation was observed to be a major degradation reaction for phorate and p. sulfoxide in both soils. Parallel bioassay tests indicated that, in sand, the biological action of "phorate" was due to the joint action of the three compounds. In a field study phorate EC, applied as a broadcast application at 3.4 kg AI/ha and incorporated into the top 7–8 cm of soil was slightly more persistent in muck than in sand. More than 99% and 98% of the applied phorate and its oxidation products disappeared from the sand and muck, respectively, within a year of treatment, indicating that the residues were only moderately persistent under climatic conditions encountered in southwestern Ontario. Low residues of p. sulfoxide and p. sulfone were detected in radishes grown on both soils in the first year but none were present in the second year. No residues were detected in carrots grown on either soil.

Pheromone trap density is one factor which influences the magnitude of catch and therefore, should be standardized in a monitoring program. Trap catch increased with the area served by a trap, but reached a plateau when the trap density fell below one trap per 7 ha. From these data a quadratic regression was developed which relates the relative increase in trap catch to trap area. This relationship can be used to compare monitoring data obtained with different trap densities.

The number of moths previously caught in a sticky trap can affect its future performance. In the Pherocon® 2 trap catches began to decline after a cumulative total of 20 to 30 moths and in the Pherocon 1CP after 50 to 70 moths. The catch totals causing a drop in trapping efficiency were correlated with the size of the adhesive catch surface. The cause for the loss in trapping efficiency appeared to be physical deterioration of the adhesive due to moth scales, other insect parts, or dust rather than an olfactory repellent factor. Trapping efficiency was restored by thoroughly stirring the soiled adhesive. Standard maintenance procedures should be followed to keep the adhesive quality of the catch surface constant and thereby prevent a reduction in catches. Tests with two pheromone dispensers, the Codlemone® rubber septum and the Conrel® microfibres, indicated that both are effective for at least 6 weeks. Codlemone septa resulted in higher catches during the first week of field use. During subsequent weeks there was no difference in attractiveness between the two pheromone lures.

Influence of temperature and moisture on black cutworm, Agrotis ipsilon (Hufnagel), development and reproduction was studied on field corn. The black cutworm spends portions of its life above and below soil, consequently influence of temperature and soil moisture and temperature and relative humidity (R.H.) was determined. Temperatures of 34°, 27°, and 20°C were used with 18%, 24%, and 30% soil moisture and with 40%, 60%, and 80% R.H. In addition, a treatment of 13 °C and 60% R.H. was included.

Temperature was the only factor influencing development of all stages, with 27°C the optimum temperature studied. Soil moisture did not influence larval development, but relative humidity affected the first five instars. Larvae required from 6 to 9 instars to complete development, with temperature and relative humidity affecting the number of molts. Head capsule measurements varied depending on the number of molts required for development. Fecundity was greatest at 27° and 20°C, and at 60% and 80% R.H. The optimum treatment for reproduction and adult survival was 20°C and 80% R.H. Many females failed to lay fertile eggs at 34° and 13°C.

Scymnus marginicollis Mannerheim was reared on green peach aphids, Myzus persicae (Sulzer). At 20°–25 °C and a 16-h photoperiod, durations of egg, larval, and pupal stages were about 5, 10, and 7 days, respectively. Adults survived more than 80 days. The ingestion of wax-producing prey was not required for the beetle larvae to produce their woolly wax covering. Larvae fed exclusively by sucking fluids from appendages of the aphid prey. The coccinellid consumed about 16 adult aphids during the larval stage. Adults fed on fluids and tissues of M. persicae. Female adults consumed about five aphids per day, nearly twice as many as did males. The beetle populations increased in July and reached peak abundance in August. The seasonal trend of S. marginicollis suggests one generation per year.

Natural infestations of cereal aphids caused significant reductions in grain yield in field plots of early and late cultivars of barley, wheat, and oats in southwestern Quebec. Severely reduced grain yields resulted when caged plants of wheat and late cultivars of barley and oats were artificially infested, but early cultivars of barley and oats were less affected. The percentage protein of grain was significantly reduced in all crops, but wheat and late oats were most affected.

The relationship between body size and age in two species of Collembola, Folsomia Candida and Xenylla grisea, was studied in three temperature regimes. Power curves were used to describe length as a function of age for each species-temperature combination. Growth parameters (slopes of the log-log curves) and length at hatch (log intercepts) were compared by multiple regression. There was a strong non-linear effect of temperature on growth in the range normally encountered.

Morphological interpretations are given of sclerotized areas, such as the prothoracic shield, anal plate, and pinacula of lepidopterous larvae. Markings of these sclerotized areas which indicate the positions of muscle attachments are classified; new systematic names are suggested based on those of the corresponding muscles. The importance of sclerotized areas and markings for larval classification are shown by examples. These markings are used to distinguish certain closely related species of the genus Chilo (Pyralidae).

The relationship between bark beetle infestation of ponderosa pine and severity of infection by Ceratocystis wageneri was investigated by closely monitoring 256 trees (136 apparently healthy, 60 moderately diseased, and 60 severely diseased at initiation of study) for beetle infestation from summer 1972 to fall 1975. Disease ratings were updated by periodic examination, and some trees changed disease category during the study. Ninety trees were infested by Dendroctonus brevicomis, D. ponderosae, or both, five by buprestids alone, and one tree died from effects of the pathogen alone. Sixty-two of the beetle-infested trees were severely diseased at time of infestation, 25 were moderately diseased, and only three were apparently healthy. Thus, the results showed that bark beetles were much more likely to infest infected than healthy trees. Among diseased trees, those with advanced infections were most likely to be infested. There was evidence that buprestids (especially Melanophila spp.) and possibly Ips spp. attacked diseased trees prior to Dendroctonus spp. infestation.

Daily periods of activity of eight colonies of the eastern tent caterpillar, Malacosoma americanum (F.), were monitored photoelectronically under a simulated springtime photoperiod in the laboratory. Colonies averaged 3.7 ± 0.1 (S.E.) activity periods per day (N = 103 colony-days), separated by an average interval of 6.6 ± 0.1 h (N = 389). Foraging trips lasted an average 2.8 ± 0.1 h (N = 397). A plot of 336 activity period midpoints (seven colonies) showed all colony activity peaks to occur between 0600 and 0800 h, 1100 and 1600 h, 1900 and 2100 h, and 0100 and 0400 h. The first three peaks correspond well to previously reported field observations but the early morning foraging trip, which occurred in darkness, was previously unreported by field investigators. The temporal placement of activity peaks shifted from day to day within colonies but the occurrence of evening foraging trips was the most consistent. Dark onset appeared to trigger foraging in resting colonies. Recruitment of hungry caterpillars to food finds appears to be a common component of the foraging strategy of this species.

The preservation of host material in a state suitable for successful development of beneficial parasite or predator species is desirable for the mass culture of entomophagous species. Thus, Coppel and Mertins (1977) report the coddling of sawfly cocoons, and Fedde et al. (1979) chilled host eggs to keep them in a susceptible state for the egg parasite Telenomus alsophilae Viereck. Such techniques are also valuable to assure continuous rearing of parasites or predators during shortages of hosts.

The latter situation pertained while we were studying factitious hosts of the thelyotokous, multivoltine egg parasite Ooencyrtus ennomophagus Yoshimoto (1975). This parasite cannot develop in embryonated eggs; therefore it is essential to hold hosts in the unembryonated condition. Faced with the loss of the typical host for 0. ennomophagus, the univoltine elm spanworm, Ennomos subsignarius (Hübner), we found that eggs of the multivoltine pipla tentmaker, Clostera inclusa (Hübner), would suffice. Field populations of the tentmaker crashed in 1979, leaving us dependent upon a small field-cage rearing of this insect for experimentation.

A polyhedrosis virus was found in collections of Bruce spanworm, Operophtera bruceata (Hulst), larvae from two locations in British Columbia in 1957 (O. N. Morris, pers. comm.). Bruce spanworm was prevalent in the Maritime Provinces and Quebec in 1963 and 1964 and a polyhedrosis virus was credited with terminating this outbreak (Forbes et al. 1964, 1965; Martineau 1964, 1965). A detailed examination of the virus from Quebec showed that it was a singly-embedded (unicapsid) nuclear polyhedrosis virus (Smirnoff 1964) which is classified as Baculovirus subgroup A (Matthews 1979).

Several instances of predation by lacewing larvae on adults of the flea beetle Phyllotreta cruciferae (Goeze) have been observed in Saskatchewan. Other reported insect predators of rapeseed-crop-infesting flea beetles in the Canadian prairie provinces are the beetle Collops vittatus Say (Gerber and Osgood 1975), and one of the big-eyed bugs, Geocoris bullatus (Say) (Burgess 1977).

The first observation of an attack on an adult flea beetle by a lacewing larva was in August 1972, when some lacewing larvae, adult flea beetles, diamondback moth larvae (Plutella xylostella (L.)) and unidentified aphids and midges were swept from maturing rapeseed near Aberdeen, Saskatchewan. One of these lacewing larvae attacked an adult of P. cruczferae in a glass collecting-vial and carried the flea beetle around in its jaws. Other lacewing larvae attacked aphids, midges, and diamondback moth larvae. Further evidence for lacewing larvae feeding on adult flea beetles was obtained in August 1979, when a sizeable population of lacewing larvae in a rapeseed crop was encountered near St. Gregor, Saskatchewan. One of the larvae swept from this crop had an adult of P. cruciferae in its jaws when it was first seen in the sweep net. Later the same day, another lacewing larva, swept from a nearby rapeseed field, attacked an adult of P. cruciferae in a collecting vial. In the laboratory both lacewing larvae, still carrying their prey, were quick-frozen, preserved in 70% ethanol and later photographed.

In Manitoba, first-stage larvae of Microctonus vittatae Mues. overwinter in diapausing adults of two rape-infesting chrysomelids, Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.). The parasite larvae resume their development in May after the hosts have finished overwintering, and mature parasite larvae emerge and spin cocoons from which adults emerge late in May and during June. Usually there are four parasite generations each year; most of the larvae in the first three generations are non-diapausing, whereas most first-stage larvae of the fourth generation develop briefly and then enter diapause in September or October and overwinter. Early attempts to propagate M. vittatae for laboratory studies were unsuccessful because most of the immature parasites either died or entered diapause. Preliminary tests suggested that, as in some other parasite species (Saunders 1965; McNeil and Rabb 1973; Anderson and Kaya 1974), the photoperiod at which the parasites were propagated influenced the incidence of diapause. The following three experiments examined this hypothesis and attempted to identify rearing conditions that would prevent diapause or limit its incidence in M. vittatae.

We reported previously (Steck et al. 1977) that equal-parts mixtures of (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-11-hexadecenyl acetate (Z11-16:Ac) attract male Crymodes devastator (Brace) moths to field traps, and that attraction is enhanced by incorporation of (Z)-7-dodecenyl acetate (Z7-12:Ac) in the lure. During subsequent studies with sex lures for this species we discovered that (Z)-11-hexadecenol (Zll-16:OH) is much more effective than Z7-12:Ac as a trapping synergist.

During 1978 many structural analogs of the sex attractant components were tested as lure synergists by adding 20% of each analog to a basic 2:l Z11-16:Ald + Z11-16:Ac lure, using numbers of males trapped as the criterion of effect. Z5- and Z7-10:Ac; Z5-, Z7-, and Z9-12:Ac; Z5-, Z7-, Z9-, and Z11-14:Ac; Z5-, Z7-, and Z9-16:Ac were tested in this way, as were the corresponding alcohols and aldehydes and Zll-16:OH. The (E) isomers of these along with Ell-16:Ald and E11-16:Ac were finally tested.