A shift in the average number of an organism from an economic to a non-economic density, the goal of biological control, is usually brought about by the addition to the ecosystem of exotic "key" factors whose lethal action is more efficient and broader in scope than that of the mortality factors already operating.Such a shift in the homeostasis of a pest population can occur only when its protection from the lethal action of key factors is fortuitous. With fortuitous protection (in contrast to absolute protection) host-searching by parasite or predator populations is so unrestricted by physical barriers that no portion of the target population is continuously immune to attack.In many instances after the attainment of low-density homeostasis the controlling action of the added key factor does not appear to be either supplemental to or superimposed on the total pest mortality that had prevailed in the ecosystem but largely a substitution for that mortality through its displacement and greatly amplified replacement. Means for verifying the responsible key factor in a given locality following the importation and establishment of a possible key factor and observations on hierarchies of such factors are reviewed.

When Rhyacionia buoliana larvae were confined with adults of the parasite Hyssopus thymus in gelatin capsules, the larvae regurgitated on the parasites and/or chewed out of the capsules. Instructions for constructing and using an electrical device for cauterizing the mouthparts of the larvae and a suction accessory for holding them are given.

A method is described for sampling aquatic insects using black light. Trap design, description of its placement, and conversion to a fumigator is explained. Total numbers of emerging insects captured by aquatic light trap are given and compared with catches in surface and bottom cone traps. Overall effectiveness of the black light trap is discussed.

A sequential egg-band sampling system for predicting defoliation of aspen by the forest tent caterpillar (Malacosoma disstria Hbn.) is described and its accuracy assessed. A probability method of predicting defoliation from the stage of the outbreak in each local area is also established. A third method, which promises to be the most accurate and consistent, is proposed. In this last system, egg-mass density is established and related to defoliation levels which are adjusted depending upon age of outbreak.

Adults of Dendroctonus ponderosae Hopkins were stored at 1 °C in 2-mil polyethylene bags containing moistened excelsior. Under these conditions, 85% of the beetles survived after 30 days. Stored adults showed no decrease in fecundity but the percentage of females in their broods increased with storage duration. Handling prior to storage and interruptions in the storage period resulted in a decrease in survival. Female adults survived storage better than males.

Several genetic insect control methods are currently available, but they are practicable only when population densities are low.In this paper we describe ways of increasing the frequencies of dominant conditional lethal genes in populations. The proposed methods should be particularly valuable for the eradication of major agricultural pests controlled at present by frequent applications of insecticide.Eradication of boll weevil populations could be accomplished by the release of relatively small numbers of artificially reared insects. The number required can be less than it is for other proposed methods by a factor of 100 or more¡¡

The tracheal system of all three larval instars of Hypoderma is metapneustic. The arrangement generally resembles that in the Cyclorrhapha except for reduction of the dorsal anastomoses, lateral, longitudinal, and spiracular tracheae and the apparent absence of ventral cervical tracheae. The transverse connectives consist mainly of secondary and tertiary branches, but the dorsal anastomoses have only secondary branches, if any. The transverse connectives extend to the ventral and lateral somatic musculature and to the alimentary canal. The dorsal anastomoses supply mainly the heart and dorsal somatic musculature.

The results of systematically conducted field observations revealed that the site of male:female assembly for mating in apple maggot flies, Rhagoletis pomonella (Walsh), was exclusively on the fruit of the larval host plant. Laboratory observations were in strong agreement with this finding.

The balsam woolly aphid, Adelges piceae (Ratz.), in Newfoundland is dimorphic and has three generations a year in the crowns of balsam fir trees. Two generations of the sistens, or diapausing form, predominate. Progredientes are more common than elsewhere in North America and occur on nearly all parts of a branch. They do not mature on current needles. The ratio of progredientes to sistentes is about 1:40 in balsam fir flowering years and 1:80 in non-flowering years. Aphid development in the spring is earliest at flowered internodes, 11 to 14 days later at 2-year-old nodes, a further 4 to 8 days later at older nodes, and latest at the shoot tips. Intra-crown and inter-tree differences in aphid development are small but measurable. Stratification of the tree crown is required for sampling during the first aphid generation.

The amount of sweet-fern was significantly related to the degree of Saratoga spittlebug adult injury to red pine on study plots in Lower Michigan. Other host plants supporting spittlebugs must be extremely abundant before populations increase enough to cause heavy injury. A spittlebug risk-rating device is presented that specifies hazard in a red pine stand by plotting per cent sweet-fern against per cent other suitable hosts.

The life cycle of Leucopis (Leucopis) verticalis Malloch, a chamaemyiid predator of mealybugs, is presented. There are at least two and probably four generations a year in northeastern Ohio, with overwintering occurring as diapausing pupae. Eggs are laid in or near colonies of Pseudococcus comstocki (Kuwana) (Homoptera: Pseudococcidae) infesting such ornamental shrubs as Taxus cuspidata Sieb. and Zucc. var. hicksii Rehd (Japanese yew) and Euonymus Fortunei (Turez.) Hand-Mazz. (wintercreeper). The incubation period requires 48–72 hours at 21°–25 °C. Larvae complete development in 12–15 days. Larvae feed by breaking through the integument of the prey with their mouthhooks and sucking out the body contents. Each larva usually kills all of the immature mealybugs within a colony before attacking the stem mother. Puparia are formed within the remains of the destroyed colony. The pupal period of non-diapausing pupae requires about 12 days. Pupae formed after mid-September enter diapause and overwinter. The entire life cycle in nature can be completed in 33–42 days if no diapause intervenes.The egg, three larval instars, and puparium are described and illustrated.

For 100% mortality, concentrations of potassium capricate, 0.0009 to 0.005 M, are very effective insecticides against Aedes aegypti (Linnaeus), particularly larvae, in the laboratory (23.00° ± 0.1 °C) within 1 to 5 days. And likewise potassium capricate, 0.001 to 0.002 M, and variously applied capric acid per se are effective against native mosquitoes in water pools in the field (5°–16 °C). With dosage–mortality tests of potassium capricate in the laboratory, larval mortality in A. aegypti was directly dependent on concentration, time, and age, tolerance increasing with age of the larvae. Although pupae seemed little affected, about 60% of the adults formed died during eclosion in 0.003 to 0.005 M mostly within 3 days. Admittedly these substances kill fish, crustaceans, and other insects, but in the field, treated pools soon regained living inhabitants. Some evidence shows that capric acid may be the least liable to endanger fish. Advantageous properties of these long-recognized insecticides include that both kill mosquitoes, both are easily biodegraded to harmless simple components, and both are readily metabolized by mammals.

A survey of the insect pests of carrots was conducted in the organic soils of southwestern Quebec with a view to establishing the presence of the carrot weevil, Listronotus oregonensis (Lec.), in this province as well as to confirm the importance of other pests damaging carrot crops. Four different methods were used to capture adults, and the root sampling method was used for establishing larval populations.The carrot weevil was captured by light trap for the first time in Quebec on 1 June 1967, but was neither recognized nor identified until June 1970 when a few specimens were obtained again by light trap set at Ste. Clotilde and by colour traps placed in the experimental fields used for the survey in 1970. Damage caused by this new pest on carrots ranged from 2.0% to 22.0% root injuries throughout the carrot growing areas of the organic soil regions of Sherrington, St. Michel, and Ste. Clotilde representing several thousands of acres. The carrot rust fly, Psila rosae (F.), was the only other carrot pest captured, but has been found to be of no importance in these areas.

A preliminary study to define a laboratory diet on which to rear the larvae of Rhyacionia buoliana (Schiff.) was made. The rearing vials were very important and gaseous exchange was essential for proper rearing and moisture levels. It was found that wheat germ appeared to contain essential components or balance of nutrients necessary for rearing this insect. Ascorbic acid also appeared to be an important component either for its nutritional value or as an antioxidant protecting other labile dietary components. It also appeared, because of the feeding habits of this insect and the length of its life cycle, that the larvae may have to be periodically transferred to new diet formulations to insure the presence of changing necessary nutrient(s). Aseptic rearing of the larvae seemed to be feasible. It was found that eggs, surface sterilized in 0.1% hypochlorite solution for 10–15 minutes, could be aseptically introduced into containers without appreciable decrease in egg hatch; however, sustained asepsis was difficult to maintain in the rearing vials employed.

Several species of ground-beetles, with main area in the interior of North America, have more or less isolated occurrences in eastern Canada. Some of them have clearly expanded their area in recent years and are no doubt late immigrants into the east; others may be old relicts. The geographical instability of the former group is explained as an eastward movement of a steppe element following the deforestation of the country, notably within the U.S.A., south of the Great Lakes.

Five genera, Annegialia new genus, Bdelyropsis Pereira, Vulcano, and Martinez, Callosides new genus, Fossocarus Howden, and Scarabaeinus Silvestri, are discussed. Four are monotypic, Annegialia ataeniformis n. sp. from the western United States, Callosides campbelli n. sp. from Colombia, Fossocarus creoleorum Howden from the southern United States, and Scarabaeinus termitophilus Silvestri from Brazil. In the last two genera, the male of Fossocarus is described for the first time, and in Scarabaeinus information on the range and host is given. A second species of Bdelyropsis, newtoni n. sp., is described from Veracruz, Mexico, and a brief discussion of B. bowditchi (Paulian) is included.

Eucosma gloriola Heinrich is distinguished from E. sonomana Kearfott, a closely related species, by using differences in morphology and distribution. E. gloriola is notably smaller in alar expanse and in size of male genitalia. The distribution of E. gloriola follows closely the natural range of eastern white pine (Pinus strobus L.), while E. sonomana follows that of ponderosa pine (P. ponderosa Laws.).Eucosma gloriola overwinters in the pupal stage in the soil. Adults emerge from late April to mid-May in eastern and southern areas, and from late April to early June in northern areas. The insect passes through five larval instars within a pine shoot. Larvae emerge from shoots and drop to the ground in early July in eastern and southern areas, and somewhat later in northern areas.Symptoms of attack and injury by E. gloriola in two- and five-needle pines are distinct from those of other eastern shoot and tip moths. The destruction of leaders is the most important injury since stunted and deformed trees result from repeated attack.Large-scale chemical control methods as required in reforestation plantings of Christmas trees are difficult to achieve. Glypta sp. was the most abundant of five parasites reared from the eastern pine-shoot borer.

The location of a previously lost holotype slide of Neosymydobius mimicus Hottes is reported. N. mimicus occurs on Quercus macrocarpa Michx. in Manitoba.

Criteria is presented for selecting ant species as predators of insect pests, and a comparison is made between species occurring in Quebec and central Europe. In conclusion it is stated that none of the ants found in Quebec are promising as control agents against forest pests.