The insecticide acephate (0.5-dimethyl acetyl phosphoramidothioate) was applied at 0.5, 1.0, and 1.5 lb A.I./gal (.058, 0.118, 0.179 kg/l.) in aqueous solution to individual Douglas-fir trees infested with western spruce budworm, Choristoneura occidentalis Freeman, larvae in central Washington using hand held ground application equipment. Application was made when larvae were in the needle mining – bud mining stage at rates ranging from 2.58 to 5.10 gal/acre (3.97 to 7.84 l./ha). For all three concentrations, mortality of larvae inside needles was 94–98% after 1 day compared with a check mortality of 18% and larval mortality inside buds was 99% after 1 day compared with 23% for the check. Regression analyses indicated that defoliation was positively correlated with the number of needles mined the current year and per cent punctured buds, and negatively correlated with larval mortality inside both needles and buds. The data suggest that when applied at the rates used, acephate has some type of systemic action and can provide foliage protection during the year of application.

An equation developed in 1972 and 1973 for predicting the number of adult pecan weevils, Curculio caryae (Horn), in pecan trees was modified to include natural survival and evaluated for estimating weevil population and for determining the initiation of control measures. This method of scheduling insecticide applications resulted in a lower infestation of pecan weevil than jarring, the most commonly used sampling method, with the same number of insecticide applications. The use of a prediction equation for estimating C. caryae populations to determine economic thresholds looks promising for the researcher, grower, or pest management specialist.

In this paper, a stochastic analysis approach for predator–prey systems modeling is developed. The states of the system are assumed to have a natural probabilistic variation. Elements of queueing theory are used to describe these variations and to obtain both the transient and steady-state results for the system. The predator is considered analogous to a service facility and the prey as customers to be served. The Holling disk equation and mantid–fly experiments are analyzed by this approach. The method provides a framework for a straightforward synthesis of the system components and is readily generalized for multiple predator systems. Furthermore, hunger and other behavioral aspects can be easily incorporated into the mathematical analysis.

Experiments were done in an attempt to ascertain the significance of the mandibular glands of nurse bees in female caste differentiation. Groups of 30 or 75, 10-day-old nurse bees, with their mandibular glands removed, were caged in the laboratory. Each group was provided with female larvae in plastic queen cell cups. The treated nurse bees were able to rear a few pupae, from these larvae, which were classified as queenlike intermediates while the untreated nurse bees reared pupae or adults which were classified as queens or queenlike intermediates.

An experimental component analysis approach is used to define the physiological interactions of carbohydrate nutrition and the manner in which it regulates the crop-emptying rate. The basic components of the crop-emptying rate are frequency of valve opening and the volume of the slug of fluid which passes through the valve. This volume is solely a function of crop volume, but the frequency of opening is a complex function determined by the crop volume, and by gut activity and blood osmotic pressure, both of which are related to nutritional parameters. To guide the formulation of the relationship, a model of the mechanism of valve function is proposed, based in the phenomenon of muscle creep.

The osmotic pressure is estimated by calculating the change in blood trehalose level estimated from observed rates of disappearance of sugar from the crop. Sugar emptying from the crop diffuses from the midgut to the blood, where it is partitioned between trehalose and glycogen according to established biochemical relationships. The model developed fits a wide variety of published data on crop-emptying rates of flies fed different volumes and concentrations of sugar, and may be applied to active, inactive, and flying insects.

An inventory was taken of aphid species occurring on balsam fir, white spruce, larch, red pine, white pine, jack pine, and black spruce at two sites where the introduced red wood ant, Formica lugubris Zett., had been released. Twenty-one aphid species were found, all in the genus Cinara Curtis. Nine of these species, and possibly a tenth, were new records for Quebec. Observations on colony size and distribution on host trees, in ant infested and control blocks, were recorded.

Field studies in Ontario, Oregon, and California on interspecific attraction and inhibition among the coniferophagous species of Choristoneura (the spruce budworm and its allies) confirmed specific pheromonal differences among the species. Of the three species that are mutually attractive and whose males are attracted by blends of trans- and cis-11-tetradecenal, C. fumiferana, C. biennis, and C. occidentalis, catches of C. fumiferana males in traps baited with C. fumiferana females were significantly reduced by the presence of females from a second group in which it is believed the females produce trans-11-tetradecenyl acetate. Catches of C. occidentalis males by C. occidentalis females were not affected in this way. F1 hybrids and backcrosses between an aldehyde-producing species and an acetate-producing species produced females that were attractive to males of one or other of the parent species, although some females were not attractive to either. Individual females never attracted males of both parent species, and of those that were attractive, more were attractive to males of the aldehyde species than to males of the acetate species. The results suggest sex-controlled inheritance and expression.

Post-attack injections of full- and half-strength Silvisar 510 (cacodylic acid) appear to inhibit populations of Dendroctonus rufipennis (Kirby) more effectively than quarter- and tenth-strength dilutions. Arsenic concentrations in the phloem were highest in the full-strength treatments and progressively decreased in the lesser strength treatments. Arsenic concentrations in the phloem were generally highest just above the frill while concentrations at 20 ft and higher above the frill were significantly lower than those just above the frill. Arsenic concentrations in the needles were highest in the full- and half-strength treatments and decreased progressively in the lesser strength treatments. Concentrations in the needles were essentially equal in the upper and lower portions of the crown. Arsenic concentrations in the soil were not affected by the treatments.

In a laboratory study, larvae of the western cherry fruit fly, Rhagoletis indifferens Curran, were successfully reared on an artificial diet consisting of wood pulp, agar, wheat germ, Brewer’s yeast, sugar, salt, choline chloride, ascorbic, citric and propionic acids, cholesterol, methyl para-hydroxybenzoate (MPH), and water. Ten other diets consisting of various ingredients obtained variable results. A premixed tropical fruit fly diet (prepared by Nutritional Biochemicals, Cleveland, Ohio) was not suitable for rearing the cherry maggots. Formaldehyde was not satisfactory as a mold inhibitor.

The eggs were obtained on artificial cherries made up of a soft ceresin wax. No oviposition occurred on the other materials tested (candle wax, a regular ceresin wax, beeswax, and silicone). Significantly (5% level) more eggs were deposited on wax cherries of orange, green, and greenish-yellow colors than black, red, white and blue. A laboratory rearing method employing orange colored wax cherries and an artificial larval diet was established for culturing the western cherry fruit flies.

The scolytids, M. mali, M. fasciatum, X. saxeseni, X. ferrugineus, and X. xylographus, were attracted consistently to black oak trees killed each month from March to August, 1974. More beetles were attracted to larger diameter trees and most were trapped on the north aspect. The beetles showed no trends for attraction for trees killed in different months.

Bacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.

The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.

The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.

Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.

The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.

A laboratory experiment demonstrated that in San Jose scale, Quadraspidiotus perniciosus (Comstock), the male is susceptible to a number of insecticides. Diazinon was the most effective as it killed the males before they emerged from their shells. Males emerged and survived for a short time before being killed by residues of azinphosmethyl and endosulfan. In an orchard, a petal fall spray of diazinon or Penncap E applied when male scales started to emerge gave good control of San Jose scale and was as effective as three summer sprays of diazinon timed to emergence of crawlers. Penncap E was ineffective against the crawlers. Post-bloom sprays are necessary to control infestations of incrusted scale because a pre-bloom oil application usually fails to contact live scale that may be underneath one or more layers of old dead scale.

Hay bales from areas of high skipper densities contained an estimated 5000 viable eggs/bale underlining the importance of passive transport of Thymelicus lineola (Ochs.) eggs in hay as a means of dispersal for this insect pest. While eggs ingested by cows did not survive it is believed that, in view of the number present in each bale, some would not be eaten and could be the source for a new infestation.

Sampling techniques for estimating egg populations of the clover root curculio, Sitona hispidula (F.), were developed in alfalfa and red clover fields in Kentucky. An appropriate sample unit was a 3 × 3 in. (7.6 × 7.6 cm) area of plants and the soil beneath it to a depth of 4–5 in. (10.2–12.7 cm). This was processed by a flotation technique. The spatial disposition of the eggs conformed to a clumped pattern in both fields. The variation of 88 to 93% in log variances was accounted for by the variation in log means. There were no significant differences in dispersion pattern between the two crops. Variance analysis revealed that block and plot differences were rarely significant but the interquadrat variance predominated. The number of samples required to estimate the population with specified level of significance and margin of error was inversely proportional to population density.

A simple bubbler for separating insects and other macroinvertebrates from aquatic bottom samples by elutriation is described. The apparatus is simple in construction and use and separated all groups of aquatic organisms from stream bottom samples with about 99% overall efficiency.

Choristoneura lambertiana ponderosana Obraztsov is commonly found infesting its main host, Pinus ponderosa Laws., in Colorado. It is also known from Wyoming, South Dakota, and Montana. Pinus flexilis James is a host in Montana, and in Colorado ponderosa pine dwarf mistletoe, Arceuthobium vaginatum subsp. cryptopodum Hawksworth and Wiens, is also utilized as a food plant. Adults fly and oviposit in midsummer; newly hatched larvae overwinter in hibernacula and emerge in the spring to feed on new foliage. Pupation takes place in the feeding area. There is one generation per year.

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.

A Howardula sp. nematode parasite of the tobacco flea beetle, Epitrix hirtipennis (Melsheimer), was able to utilize the adult male to disseminate juveniles. At 27°C the mean total number of juveniles released per beetle was 369 for female beetles and 377 for males at an average rate of ca. 37 per day from both sexes. A cooler temperature retarded the onset of dissemination but did not affect the rate of release. Fifty-nine per cent of the free-living nematodes survived for 5–6 days, but none survived beyond 13 days. Seventy-nine per cent of the free-living nematodes were female.

A method for the direct isolation of useful genetic strains was shown effective in the onion maggot. This method circumvents the extensive preliminary investigations called for by current concepts in genetic population control. From genomes treated with 1.5 kr of gamma radiation, the system showed that 17% of those tested carried chromosomal rearrangements potentially useful in genetic population reduction.

During 1971 a study was conducted to determine the amount of the various Douglasfir cone structures (bracts, scales, and seeds) consumed by the Douglas-fir cone moth, Barbara colfaxiana (Kft.), in the Buckhead Seed Production Area, Willamette National Forest, Oregon. It was not the intent of this study to develop a complete energy budget for B. colfaxiana, but rather to determine the number of calories consumed, on the average, by an individual during the larval stage. The behavior of the various larval instars has been discussed by Radcliffe (1952), Keen (1958), Hedlin (1960), and Nebeker (1977). The calorie was selected as the unit of measure due to its usefulness in modeling energy transfer from one component to another in the forest ecosystem.