Studies on the damage and losses of wheat crop caused by the migratory grasshopper, Melanoplus sanguinipes (Fabr.), were carried out under field conditions during 1972 and 1973. A significant inverse relationship was evident between grasshopper density and grain yield. Loss in yield may occur due to grasshopper infestation in different ways: (1) early hatching of grasshoppers may completely destroy newly-germinated seedlings; (2) a gradual defoliation of the crop throughout the growing season reduces yield and grade of the seed due to reduction of plants’ photosynthetic efficiency; (3) headclipping occurs towards the end of the season when leaves have been completely destroyed. The role of weather factors in shaping the impact of grasshoppers on the crop is discussed.

The fecundity of Hyssopus thymus Girault females does not normally vary between generations within a single year, but differences frequently occur between years. A weighted mean annual fecundity of 14 eggs per female under laboratory conditions has been determined by pooling several years’ records, although the maximum number of eggs laid by a female was 130. A mean of 20 eggs per female was determined under quasinatural conditions. The weight of the host, Rhyacionia buoliana (Schiffermüller) (Lepidoptera: Olethreutidae), limits the number of eggs laid per host during the early spring when shoot moth larvae are small. When the host larvae are larger, size is no longer a limiting factor in the number of eggs deposited per host. There is a preoviposition period of about 3 days and egg production is synovigenic. The number of fully developed eggs within a female at one time varies between about 7 and 12 eggs on a 3-day cycle, and never exceeds 16. Each female wasp attacks two or three large host larvae and this number is probably doubled when the host larvae available for attack are small.

Eggs, larvae, and pupae of Culex tarsalis Coquillett were treated with ecdysones, juvenile hormone analogs, and 6-oxooctanoic acid. Effects of these agents on mortality, induction of supernumerary stages, and adult emergence were determined. Topical treatment of eggs with CRD9499 (a juvenile hormone analog), β-ecdysone, and 22-isoecdysone caused a reduction in adult emergence. Treatment of fourth-instar larvae with these chemicals not only induced mortality but also caused the formation of supernumerary intermediate stages. Larvae of C. tarsalis were very susceptible to CRD9499, but pupae were resistant. The ecdysones caused some mortality but only at very high doses and would thus be of little use as larvicides. 6-Oxooctanoic acid caused high rates of mortality at 0.001 M concentrations.

Random populations of field-collected Xyletinus peltatus (Harris) beetles laid significantly more eggs on yellow-poplar than on any of seven other woods placed in a crawl space beneath a house and in a controlled environment. Egg deposition of random beetle populations when confined to individual woods was generally greatest on woods most often chosen for choice oviposition, but no significant statistical preference was shown for any wood. In tests with beetles collected in copula to ensure equal representation of sexes and that mating had occurred, yellow-poplar was again preferred for egg-laying. Variability in oviposition and fewer eggs per female by beetles collected while mating suggests that these beetles may have mated and laid eggs previously. The third test, with wood of varying ages since tree felling, suggested that beetles prefer at least some woods to be aged and also indicated preference for yellow-poplar. In all three choice experiments beetles showed a significant preference for block undersurfaces for egg-laying; this preference possibly indicated responses to changing ambient light conditions. Egg-laying females appeared to respond first to favored hosts, then to block undersurfaces or oviposition site characteristics. Both host species and wood surface features would affect susceptibility to beetle attack.

Single 15-min injections of 0.18 to 0.24 p.p.m. of methoxychlor as an emulsifiable concentrate into the Saskatchewan River removed 75 to 99% of the larvae of Simulium arcticum Mall. from 23 to 34 km sections of the river. Stronger concentrations (0.30 to 0.31 p.p.m.) eliminated about 98% of the larvae from rapids 64 km distant and an estimated 46% at a distance of 139 km. Other kinds of aquatic larvae in exposed sites were also affected: Plecoptera to about the same degree as the Simuliidae, followed by Ephemeroptera, Trichoptera, and Chironomidae (least affected). Larvae in sand were not affected. Populations of Chironomidae, Trichoptera, and Ephemeroptera in many sites were completely restored within 7 to 14 days after a single treatment. Fish were apparently unharmed. Residues were negligible and short lived.

Potential outbreaks of S. arcticum were averted by all of the experimental injections of methoxychlor except that of 26 May 1970. In this test an outbreak that killed four animals occurred because a 15-min, 0.207 p.p.m. dosage eliminated only about 23% of the black fly larvae in an adjacent portion of the river.

Examination of the most commonly used criteria for separating instars in larval chironomids, based on a study of 29 species from three subfamilies in Marion Lake, British Columbia, revealed that only head capsule width or length is suitable. Most chironomids appear to have four larval instars.

Discovery of the "lost types" of Xiphidium glaberrimum Burmeister, 1838, has made possible the clarification of use of several names which have been used for two species of Orchelimum. O. glaberrimum is shown to be the senior synonym for the species known as O. vulgare Harris, 1841. To preserve stability, an application has been made to the International Commission on Zoological Nomenclature to suppress both glaberrimum Burmeister and cuticulare Audinet-Serville, 1838. O. erythrocephalum Davis, 1905, is removed from synonymy with O. glaberrimum, and is the valid name for that species. Characters for distinguishing vulgare and erythrocephalum are discussed and illustrated. Type specimens are designated for glaberrimum, cuticulare, and vulgare.

A sex pheromone trap was studied as a quantitative sampling device in a biological monitoring scheme for codling moth populations in Michigan apple orchards. Factors influencing trap efficiency and the relationship of trap catch to adult moth density and the overall seasonal dynamics of L. pomonella are considered.

By correlating seasonal male moth catches to absolute infestation levels at harvest it was possible to indicate the density response of male moth catches in the pheromone trap (Sectar 1). Catch response was non-linear and the trap ceased to be indicative of higher infestation levels when accumulative catch exceeded about 100 moths/trap. Also, accumulative trap catches from the first few weeks of the season (before damage appeared) correlated well with eventual infestation levels indicating possible use of the pheromone trap as a predictive tool. Of the many factors influencing trap catch size the number of moth productive trees serviced by a trap (trap/tree ratio) was shown to be of critical importance.

The European earwig is an excellent experimental animal for many laboratory and field studies of insect ecology and behavior, but special rearing, marking, and trapping techniques are required to exploit the insects’ potential fully. This paper describes an artificial nest and associated techniques which reduce rearing mortality below 10%. Methods of studying events in natural nests, and of capturing and marking individuals for population studies, also are described.

When trichloronat or fensulfothion was applied to the soil surface, the toxicity of both compounds to first stage root maggot larvae increased during the first few days, then decreased at a constant and relatively rapid rate. When trichloronat was mixed with the top 1 in. of soil, its toxicity or that of its metabolites increased for about 3 months, then gradually decreased. When it was applied in a band below the surface, its persistence increased with the depth of application. When fensulfothion was applied in the same manner, its toxicity was not greatly influenced by the method of application; this decreased during the first 4 or 5 days, rose to a peak in 15 to 30 days, then gradually decreased. Fensulfothion was highly systemic in rutabagas. Its toxicants were most bioactive 60 to 80 days after application and decreased gradually thereafter. Trichloronat toxicants were slowly absorbed by the roots but toxic residues did not degrade in storage.

The Holarctic species of the genus Pygocryptus Roman (Hymenoptera: Ichneumonidae) are revised. Two previously recognized species, P. grandis from Europe and P. echthroides from North America, are retained; four new species and three subspecies for P. echthroides are proposed. A diagnostic key and descriptions of the new species and subspecies are presented.

In 1966, Ueno described and figured a nymph as Ephemerella sp. from a series of 12 specimens collected by the Kyoto University Pamir–Hindukush Expedition in 1955. Allen (1971) named this mayfly E. borakensis from Ueno's description and figure, and placed the species in the subgenus Drunella Needham.

Six species of Apanteles (Hymenoptera: Braconidae) that attack microlepidopterous larvae in growing tips of spruce and fir are described, figured, and keyed. They are: A. fumiferanae Vier., A. petrovae Walley, A. absonus Mues., A. renaulti n. sp., A. milleri n. sp., and A. morisi n. sp.

Ths paper describes and illustrates, with photomicrographs, the gross histological development of stages of the endoparasitoid Exoristobia philippinensis Ashmead in the puparia of three synanthropic flies under laboratory conditions. The major organ systems, especially nervous, digestive, reproductive and respiratory are traced.

A Bacillus thuringiensis Berliner formulation, with and without chitinase, was tested on various instars of Lambdina fiscellaria fiscellaria Guén. reared under various temperature conditions. The results revealed that resistance to infection increased as larval development progressed and at lower temperatures. At a given temperature, 65% of third-instar larvae died after 5 days while only 10% of fifth-instar larvae died in the same period. Chitinase increased the efficiency of B. thuringiensis for all larval instars and at all temperatures.

Studies of the population dynamics of the Semiothisa complex in Manitoba larch bogs indicated that the fluctuations in the numbers of this complex were clearly related to mortality in the pupal stage, which is therefore a “key” stage. Density-dependent factors are evidently operating in the dynamics of these insect populations. Interrelationships exist between the various Semiothisa species and also between looper and larch sawfly numbers.

Synopeas osgoodi n. sp., associated with balsam gall midge, Mariaville, Me., U.S.A., and Platygaster kimballi n. sp., associated with thistle, Houlton and Belfast, Me., U.S.A., are described herein.

Under field conditions, as well as in the laboratory, the critical photoperiod for the formation of sexes in the pea aphid, Acyrthosiphon pisum (Harris), is from 13 h and 15 min to 13 h and 17 min. The fecundity of this aphid on the pea variety Lincoln under field conditions is similar to that obtained in the laboratory (maximum 66 ± 10 and a minimum of 35 ± 12 individuals).

Up to 47% males and 80% oviparous females were produced under field conditions. This percentage is less than that obtained in the laboratory where 57–63% males and 90% oviparous females were produced.

When Hypera postica (Gyll.) was held at 11 constant temperatures, the hatching rate for eggs increased with rise in temperature from 8° to 20 °C and remained maximal to 32 °C. None hatched at 6 °C. Larvae survived at 10° to 35 °C with high mortality only at these limits. Pupae survived at all temperatures above 10 °C but at 35 °C half of the adults were deformed. Duration of all stages decreased with rise in temperature up to 32 °C. Developmental rates plotted against temperature did not deviate significantly from fitted curves of the form 1/y = K/(1 + ea−bx).

The optimum temperature, based on maximal rates of development and survival, for eggs and young larvae was near 32 °C and for older larvae and pupae, 30 °C. Accumulated degree-days above a base of 10 °C during development of H. postica at two Ontario locations did not differ significantly from thermal requirements calculated.

Where the insecticide Zectran was used to protect foliage from feeding of the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), the per cent parasitism of dipteran parasitoids (Tachinidae) showed a statistically significant lower value. In treated areas, the per cent parasitism of the hymenopteran Ephialtes ontario (Cresson) (Ichneumonidae) was lower; Meteorus trachynotus Viereck was about the same; Apanteles fumiferanae Viereck, Glypta fumiferanae (Viereck) (Braconidae), and Trichogramma minutum Riley (Trichogrammatidae) were greater. None of these differences was statistically significant. Results were consistent for the 2 years of study with the exception of E. ontario which showed a significant lower percentage parasitism in areas treated 1 year. Absolute population numbers of parasitoids were lower than is suggested by comparisons of apparent parasitism levels. The lowest absolute numbers were found in tachinids and E. ontario. Parasitic hymenopterans and dipterans were among the adult insects killed by the aerial application of Zectran but none of the species collected was a major spruce budworm parasitoid.