Considerable evidence substantiates the idea that native pests can be controlled by parasites and predators of allied species and genera. In a survey of 66 pest species, which were successfully controlled by biological means and for which the habitats of all species could be verified, it was found that 39% were controlled by an introduced parasite or predator of an allied species or genus. Although relatively few attempts have been made to control native and imported pests with parasites and predators of species allied to the pest species, the proportion of successes is surprisingly high. Employing these species has certain advantages, especially in the control of imported pests, because no ecological homeostasis has evolved and the association between the parasite and host (predator and prey included) is new.

Granular heptachlor applied with the seed caused mortality in larvae of the wheat stem sawfly, Cephus cinctus Nort., in wheat stems. Half a pound of actual heptachlor per acre gave less control than either 1 or 2 pounds, although the latter two rates did not differ in effectiveness. Formulations with attaclay were more effective than with vermiculite.

The insecticide was most effective in the lower internodes of the stem where it caused considerable mortality of early-instar larvae but was less effective on more mature larvae.

To be effective, heptachlor evidently required light sawfly infestations restricted mainly to the lower internodes of the stems such as had occurred in 1960. In that year heptachlor gave its best control although it was no more effective than a moderately sawfly-resistant wheat. Lack of control in 1961 was related to the heavy sawfly infestations in that year. The poor control in 1962 was related to the concentration of most of the sawfly eggs in the top two internodes where the insecticide had little effect on newly-hatched larvae. Only later, when they were more mature, did the larvae reach the lower internodes.

An artificial key is presented to separate the second to fourth instar mosquito larvae of eastern United States and Canada, west to and including Texas and Manitoba. A second, natural key, separates the genera and many of the subgenera. A list of the 134 included species and subspecies with their ranges within this region is given, with indicated corrections since Carpenter and LaCasse (1955) and the Stone et al. (1959) catalog. Larvae of two species are unknown.

Counts of the Colorado potato beetle on potato did not conform to the Poisson distribution, there being an excess of uninfested and highly infested hills over the expected numbers. However, when observed distributions were fitted to the negative binomial series, the discrepancies were not significant when tested by chi-square. The negative binomial parameter k tended to increase with density. Using a common k, the distribution of the various stages may be described by expansion of (q − px)−k, when values of k are as follows: adult, 1.95; egg mass, 4.10; first instar, 0.68; second instar, 0.78; third instar, 1.04; fourth instar, 1.07.

For all stages, the variance was proportional to a fractional power of the mean. Use of the individual potato stalk as a sample unit had little effect on the skewness of the distribution. Four transformations are offered for stabilizing the variance of field counts.

An attempt was made to suppress an incipient spruce budworm outbreak in the Lower St. Lawrence region of Quebec through the aerial application of DDT. Operations began in 1960 and continued in 1961 and 1962 when they finally met with success. Failure to achieve success earlier was due partly to the exceptionally favourable survival conditions for the insect in 1960, and partly to the inadvertent omission of a small infested area from the program in 1961. The operations greatly reduced spruce budworm populations each year in the outbreak area, while the action of natural control factors, including parasites and predators increased. The collapse of the outbreak was the result of the combined effects of the chemical treatments and of natural control factors.

A method for continuous rearing of the carrot rust fly, Psila rosae (Fabricius), has been developed for the first time. All stages of the rearing were conducted in a temperature cabinet maintained at 64 ± 2°F. Adults in a screen cage were fed water, honey, soybean flour and yeast. The females oviposited in the soil of potted carrots. Eggs were periodically removed with the top layer of soil to gallon jars containing several carrots layered in muck soil.

Field collected puparia emerged satisfactorily at 70°F., but not at higher temperatures. In the laboratory population there was a preponderance of males. A generation of carrot rust flies was completed in approximately 80 days.

A new species of Acropsilus from the Solomon Islands is described, and a key provided for the four known species of the genus.

By comparing the number of moths caught in box-type traps, attractant light sources can be arranged in the following order of efficiency: 15-watt fluorescent rubes emitting ultraviolet and visible light > 15-watt fluorescent tubes emitting cool white light ≥ germicidal rubes behind glass > 15-watt fluorescent tubes emitting ultraviolet but little visible light ≥ 100-watt mercury-vapour bulbs emitting ultraviolet but little visible light. Noctuoid and large geometroid (sent. lat.) moths discriminate between these light sources on the basis of their spectral content, but pyraloids, other small microlepidoptera and some geometroids probably do not. Pyraloid moths escaped in significant numbers from traps with normal apertures (13/4-inch), after sunrise. They freely entered traps with narrow apertures (1/2-inch) but these traps caught fewer large moths.

Studies in 1961 and 1962 showed that several naturally occurring conditions suppress the pear psylla. Temperatures above 100°F. caused mortality of nymphal stages and reduced adult oviposition. Crystallization of honeydew was a mortality factor in a few instances, and seemed to be associated with high temperature and low humidity. Absence of new growth and poor condition of leaves caused a steady decline in pear psylla numbers in abandoned orchards. Anthocoris antevolens White was an effective predator in unsprayed orchards and significantly reduced pear psylla populations. A parasite, Trechnites insidiosus (Crawford) was encountered, but its significance as a mortality agent was not determined.

This is the second of two papers on this subject. The eggs of R. buoliana are usually found singly or in small groups on the hark or needle sheaths of new shoots, except under conditions of severe infestation where new foliage is in short supply. The first two instars feed on needles from within webs. Third-instar larvae mine one or more buds and cease feeding in late summer before the advent of unfavourable temperatures. Low temperature, lethal to overwintering third-instar larvae, is one of the most important and readily measured mortality factors, Larvae spin webs and moult before they resume feeding in April or May. Migration, usually upward in the tree crown, and web construction continue throughout the spring feeding period. Larvae within two feet of the ground surface on trees less than eight feet tall complete their development earlier than larvae at higher levels. Parasitism, based on previous extensive surveys, has very likely been underestimated.

In southern Alberta the fundatrix of P. betae hatches from the overwintered egg in late April and early May and feeds on an emerging leaf of P. angustifolia or P. balsamifera, forming a gall. In the gall it produces alate fundatrigeniae, which migrate from the poplars to beets and produce apterous alienicolae. This form of the aphid reduces both yield and sugar content of beet roots. During the summer several generations of alienicolae are produced. In the fall most of the alienicolae produce sexuparae. These migrate from beets to poplars, where they produce males and oviparae. Each fertilized ovipara lays a single egg on the bark of a poplar tree. The species may overwinter as eggs on the poplars or as alienicolae in the soil. The egg has an obligatory diapause that is terminated by exposure to low temperature. The fungatrigeniae migrate from late June to mid-August and the sexuparae from early September to late October. The potential reproductive capacities of the fundatrix, fundatrigenia, sexupara, and ovipara averaged 163, 13, 6, and 1, respectively. Under greenhouse conditions 20 aphids (alienicolae) produced 9,000 in 6 weeks when the soil temperature was maintained at 27 °C. Below 15 °C. the rate of reproduction was low and death was caused by exposure to 30 °C. for 6 weeks. The most important predators of P. betae were the anthocorid A. antevolens, the flies S. bigelowi, L. pemphigae and T. glabra, and a coccinellid Scymnus sp.

Records obtained over a period of six years revealed that the Elaterid beetles in organic soils in southwestern Quebec emerged during the second and third weeks of May when the maximum soil temperature varied between 39 and 57°F and the maximum air temperature between 57 and 80°F. Males appeared earlier than females, the proportion of males becoming larger as the population decreased. Peaks of emergence occurred mostly during the first and second weeks of June when the air temperature varied between 74 and 82°F. Adult populations decreased from the beginning of June to disappear completely by the middle of July. The flight period lasted 73 and 52 days when the maximum daily temperature during the month of May averaged 62.4 and 70°F respectively. Of eleven species, Dalopius pallidus Br., Melanotus communis-fissilis complex and Agriotes mancus (Say) were the most numerous species collected in flight-traps, whereas Dalopius pallidus Br., Hypolithus abbreviatus (Say), Ctenicera tarsalis (Melsh.), Agriotes mancus (Say), and Aeolus mellillus (Say) were respectively the five most abundant species attracted by the solution of dilute molasses in heap-traps. Most of Elaterid beetles were captured when flying south. Beetles were captured at all heights from 15 to 75 inches. The population of adults decreased rapidly after two years of clean cultivation in the area surrounding the experimental plots.

Laboratory studies showed that eggs of Hylemya brassicae required 34 and 67 day-degrees at 10° and 30 °C. and 49 day-degrees at 15°, 20°, and 25 °C. to hatch when 7.2 °C. was used as the threshold temperature for development. Factors that were lethal to the eggs were temperatures above 41 °C. for one hour and periods of desiccation of 1, 1, 2, 5, and 9 days at 30°, 25°, 20°, 15°, and 10 °C., respectively.

First-instar larvae survived for approximately 2, 3, 5, and 8 days without food at temperatures of 20°, 15°, 10°, and 5 °C. Starvation for 24 hours immediately after hatching reduced initiation of feeding only slightly.

Mortality of immature Nasonia vitripennis (Walk.) was least on young house fly pupae (less than 48 hours old, at 24.5 ± 0.5 °C.) and increased with increasing host age. Increased mortality on old hosts was manifested principally as a decrease in female adult progeny, numbers of adult males and of mature diapause larvae remaining approximately constant. Reduction in the percentage of females in the adult progeny reared on old hosts probably resulted from superparasitism. This kills more female than male larvae and occurred more commonly on old hosts, each of which provides a smaller quantity of suitable food for the immature parasites. Adults reared on old hosts were smaller and relatively fewer of them were able to emerge. The proportion of the total mature parasite progeny that remained in diapause was greater on old hosts, probably because of qualitative differences in the food provided by hosts of different ages.

The searching behaviour of fifth-instar larch sawfly larvae on artificially defoliated tamarack branches and trees is discussed. Local defoliation is shown to be capable of causing appreciable mortality among early-instar larvae if feeding damage by earlier colonies forces them to wander in search of food. Air temperature affects the distance and rate of such larval movement. A considerable proportion of dislodged fifth-instar larvae are able to reach foliage and resume feeding on nearby host trees.

Rhodobium porosum (Sanderson), an aphid found on strawberry and rose, is discussed in this paper. The sexuales are redescribed and measurements given for the apterous and alate viviparous female.