Infections of Nosema pyrausta (Paillot 1927) Kotlan 1928, in egg masses of Ostrinia nubilalis (Hübner) used to artificially infest maize did not significantly decrease the ability of the infected larvae to migrate to adjacent plants. When 25% of the egg masses placed on the plants contained N. pyrausta, the resulting larvae had an incidence and an intensity of infection significantly greater than those of the controls. If 100, 75, 50, and 25% of the infesting eggs were infected by N. pyrausta, the number of larvae per plant were reduced by 72.0, 44.0, 29.3, and 38.7% respectively. N. pyrausta was transmitted via contaminated frass. The result was a reduction in populations of O. nubilalis larvae.

Second-stage nymphs of the leaffooted pine seedbug, Leptoglossus corculus (Say), were highly susceptible to most of 34 topically applied insecticides, twenty-six chemicals ad Ld50 values of less than 5 μg/g of body weight. Nine insecticides — aldicarb, aminocarb, azinphosmethyl, carbofuran, dicrotophos, FMC 45498 ((−)-(Cyano) (3-phenoxyphenyl)-methyl (+)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylate), monocrotophos, propoxur, and SD 43775 (Cyano(3-phenoxyphenyl)methyl-4-chloro-alpha-(1-methylethyl)benzeneacetate) — had LD90 values of less than 1 μg/g of body weight. There was good agreement between the relative toxicities of insecticides applied topically to the leaffooted pine seedbug in these laboratory tests and the effectiveness of several insecticides previously tested in the field.

The radiosensitivity of a wild-type (+/+) laboratory strain of Tribolium confusum Jacquelin duVal was compared with that of an extra-large (xl/xl) strain known to differ in only a single locus. Differences in both longevity and fecundity between the two strains after irradiation were very highly significant (p < 0.001), but real differences between strains in these biological characteristics may have produced the differential response. When differences in longevity and fecundity were corrected for the unirradiated control, there were only minor differences in response between the two strains. Thus, physical size alone apparently did not greatly influence the comparative radiosensitivity for the two strains of this species.

The sunflower moth, Homoeosoma electellum (Hulst) is a constant and damaging pest of cultivated sunflowers in Texas, Nebraska, and California. It was reported in Canada from Manitoba and Saskatchewan as early as 1936. Present studies begun in 1975 show that it can cause economic damage to cultivated fields in Saskatchewan. Field observations also indicate that this pest does not overwinter in Canada but that adults fly, or are blown in, from the south each year.

An efficient method of rearing this pest in the laboratory was developed and observations on its life history and behaviour, especially courtship and mating behaviour, are reported herein.

In order to establish a functional relationship between damaged pine tips apparently infested with Nantucket pine tip moth, Rhyacionia frustrana (Comstock), and within-tip larval and pupal population, X-ray techniques were used to determine numbers of actually infested tips and the numbers of tip moth immatures contained therein. Linear relationships existed between these variables and changes in tip moth density. The effect of different plantations, tip moth generations, season, and tree age did not significantly alter the observed relationships. Approximately 40% of the damaged (i.e. apparently infested) tips were actually infested, and these tips contained an average of 1.4 tip moth immatures per tip. The equation Y = −.509 +.57X estimates the number of tip moth immatures, given the number of apparently damaged tips per tree (r2 =.71).

The 10 North American species of Mycetochara Berthold are reviewed. All species are redescribed and one new species, marshalli, is described from California. Former treatments of the species of the genus have considered males and females as separate species. This review associates all known males and females. The following new synonymy is presented: megalops Casey and nigerrima Casey (= fraterna Say); tenuis LeConte, gilipes Casey, and lecontei Borchmann (= foveata LeConte); lugubris LeConte, horni Dury, and davisi Hatch (= analis LeConte); marginata LeConte and longula LeConte (= binotata Say); longipennis Casey (= pubipennis LeConte); and pacifica Casey, nevadensis Casey, crassulipes Casey, downei Hatch, angusta Hatch, malkini Hatch, and caseyi Hatch (= procera Casey).

A key is presented to aid in the identification of the species. The male terminalia are illustrated for all species except haldemani and lata, which are known only from females.

In Manitoba, the emergence of Bessa harveyi (Townsend) adults is well synchronized with the availability of larvae of its major host, Pristiphora erichsonii (Hartig). Mating occurs within 3 days of emergence and the females begin egg-laying 1–2 days later. Mean longevity was about 7 days for males and 12 days for females. Total egg production per female averaged 40 and 30 in 2 years with a maximum of 169 eggs from a single female. The total number of eggs laid per female was positively correlated with temperature.

Larvae of 13 species representing eight genera and seven families of Arrenuroidea are described, including those of Momonia marciae Habeeb, Midea expansa Marshall, Midea alaris Young (? = M. determina Marshall), Laversia berulophila Cook, Mideopsis (s.s.) crassipes Soar, Mideopsis (s.s.) borealis Habeeb, Mideopsis (s.s.) marshallae Cook, and Mideopsis (Xystonotus) aspera (Wolcott) for the first time. Diagnoses and keys are provided for the genera, subgenera, and species groups involved. Information on host associations is given for each species. Observations on morphology and host associations of these larvae provide the basis for an original, though preliminary, outline of phylogeny in the superfamily.

Newly-hatched larvae from a selected (S) “non-diapausing” gypsy moth strain and larvae from field-collected wild (W) eggs were reared in field cages in Connecticut, U.S.A. beginning May 1976 to determine developmental rates and interbreeding potential. Reciprocal and inter se matings between S and W moths were monitored to determine if hatch occurred during the fall and if S and reciprocal F1 hybrid (SW, WS) eggs could successfully overwinter and hatch at an appropriate time the following spring. Hatch of S eggs did occur in the fall. Survival of SW, WS, and some S eggs over the Connecticut winter demonstrated that this non-diapause colony is not suitable for a genetic control program in which the non-diapause trait is expected to act as a conditional lethal.