The North American genus Ceratagallia Kirkaldy, 1907 is redefined to include subgenus Aceratagallia Kirkaldy, 1907 (= Ionia Ball, 1933, syn.nov.) with 78 species in two subgenera. Two additional new species are unplaced to subgenus: C. acerata from Oregon, and C. emarginata from Mexico. The typical subgenus Ceratagallia has 30 species, including C. gillettei (Osborn & Ball, comb.nov.), C. sordida (Oman, comb.nov.), and two new species C. ana from Mexico and C. vipera from Washington state. Subgenus Aceratagallia has 46 species, all new combinations under Ceratagallia. The economic "species" formerly known as "sanguinolenta" is divided into the Canadian clover leafhopper C. humilis (Oman) and the American clover leafhopper C. agricola sp.nov. Other new taxa in subgenus Aceratagallia include 18 new species and seven new subspecies: alaskana (ssp. of siccifolia) from Alaska; omani on the Pacific coast from Oregon to British Columbia; clino and lophia from the Oregon interior; compressa (ssp. of siccifolia), gallus, modesta, okanagana, and zacki (ssp. of nanella) from intermontane valleys of the Pacific northwest and southwestern mountains; interior (ssp. of humilis) and rossi from the Sonoran subregion; australis (ssp. of nanella), coma, ebena, entoma, falcata, oionus, and venosa from Mexico and Texas; alvarana (ssp. of humilis), cerea, cristula, harrisi, semiarida, and viator widespread between the Appalachian and Rocky Mountains; and whitcombi (ssp. of robusta) from Florida to Arizona. Four former species are reduced to subspecies: compacta Oman and poudris Oman in C. robusta (Oman), helveola Oman in C. cinerea (Osborn & Ball), and truncata Oman in C. humilis. The taxa are keyed and illustrated, and their phylogeny is discussed.

The eggs of several species of cutworms of the subgenera Chorizagrotis, Crassivesica, Longivesica, Orosagrotis, and Pleonectopoda in the genus Euxoa Hübner are described. Within the genus eggs are of two main types, those with smooth chorions and those with ridged chorions, but all have the same basic chorionic design. Variations in the degree of ridging and in the detail of the design make the egg useful for species determination, and a key to some species is provided. However, the egg is of little value in distinguishing the subgenera as they are currently constituted.

UC-62644, a moult-inhibiting insect growth regulator (IGR) belonging to the benzoylphenylureas, had an EC50 of 0.1 to 0.2 ppm in a meridic diet for the 3rd to 6th larval instars of the spruce budworm, Choristoneura fumiferana Clemens. The effects of the IGR were apparent in less than 48 h after ingestion and there was evidence for some contact toxicity. The larvae were unable to discriminate between IGR-treated and untreated diet. Experimental aerial application of the IGR revealed that at <70 g in 4.7 1/ha (1 oz in 0.5 U.S. gal/acre) it effectively controlled spruce budworm populations and afforded foliage protection. These results were comparable with those obtained with Matacil® applied at the recommended rate.

An onion maggot, Hylemya antiqua (Meigen) (Diptera: Anthomyiidae) strain, having low level (≤ × 5) resistance to organophosphorus insecticides, was selected with parathion to determine if higher resistance levels to the selection agent and other insecticides used for onion maggot control would result. Parathion resistance levels increased to ×10.1 and ×23.8 after 4 and 14 generations of selection, respectively; without further selection, resistance levels declined by ca. 1/2 in 6–7 generations. Parathion resistance was ×24.4 after 20 generations of selection and resistance levels to ethion, diazinon, fonofos, and carbofuran were 2 to 3 times higher than those measured initially. The pattern of resistance development in field strains of onion maggot collected in 1975 and 1980 was similar to that observed in the laboratory selection program, but resistance levels were lower, probably because of lower selection pressure and the variety of chemicals used under practical conditions. After 14 generations of parathion selection, resistance levels were ×23.8 and ×10.1 to parathion and carbofuran, respectively. After 12 additional generations of carbofuran selection, carbofuran resistance increased to ×31.2, while the level of parathion resistance remained the same.

Severe mortality (93%) of overwintering larvae of emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), was recorded in March 2016 from green ash, Fraxinus pennsylvanica Marshall (Oleaceae), in Syracuse, New York, United States of America. In contrast, larvae collected from the same area in January exhibited <1% mortality. A strong cold front moved across New York from 13 to 15 February 2016 with temperatures plunging to nearly −40 °C in some areas. In many regions of New York where A. planipennis is established, temperatures dropped well below the reported supercooling point of overwintering larvae. To evaluate whether the extreme cold was linked to extensive mortality of larvae, trees were sampled from four areas that experienced a gradient of minimum temperatures on 14 February 2016. Overwintering mortality varied from ⩽5% to 93% among regions, with lowest survival in the coldest regions. When excised from their galleries, dead larvae were discoloured with brown spots or had black necrotic tissue in the spiracles or foregut. This is the first report of extensive cold-related mortality for this species in North America and highlights the stochastic nature of climatic extremes on invasive species populations.

Pine oil effectively reduced feeding by the white pine weevil, Pissodes strobi Peck, in a laboratory feeding bioassay utilizing agar discs containing dry, powdered bark of its host Sitka spruce, Picea sitchensis (Bong.) Carr. Possible utilization of pine oil under field conditions is discussed.

A 4000-ha block of spruce budworm, Choristoneura fumiferana (Clem.), infested forest in western New Brunswick was sprayed repeatedly in 1975 during the larval stage of budworm development. The objective was to reduce the population of the 1975 generation to a minimum level so that most of the following generation eggs found on the block could be attributed to invading females, thus providing data on the impact of moth invasion.

The presence of dispersing adults in the airspace over the block was monitored by a ground-based radar unit while light traps and pheromone-baited traps were used to confirm that invasion had taken place. A total egg population of 33.8 masses per m2 of foliage was found on the block and indirect estimates suggest that invading females deposited about 10 of these masses.

The distributions of Scolytus ventralis LeConte attacks, emergence, and parasites were studied by stratified sampling of 20 grand fir. Of the theoretical distributions tested the negative binomial gave the best fit to all three sets of data. Three sample unit sizes were analyzed (1/4, 1/2, and 1 sq. ft) and all gave similar estimates of the mean, although the smallest sample unit influenced the distribution by increasing the frequency of the zero class. Approximate normality was achieved by applying logarithmic transformation to the attack data and the Taylor power transformation to the emergence and parasite data. Analysis of variance showed that the vertical position of the sample in the tree was die most consistent factor influencing the distribution of attacks, emergence, and parasitism, while cardinal aspect had little effect. Considerable variation also occurred among trees within a group. The density of attacks was extremely variable both within and between trees, although it was slightly higher on rough bark. Emergence was generally greater in the basal half of the tree, being reduced in the upper levels by competition with other insects. Emergence increased with attack density up to about 13 attacks per square foot. Thereafter survival was probably limited by intraspecific competition. Parasitism appeared to be reduced near the base of the tree by thick bark and at the top by lack of host larvae.

Sampling designs for the fir engraver will have to consider variations between trees and vertical strata within the tree.

Twenty species of predaceous mites were collected from apple foliage in Maine during a 2-year survey of commercial and abandoned orchards. Phytoseiids and stigmaeids comprised 97.3% of the total mites. The phytoseiid Amblyseius fallacis (Garman) was the predominant predaceous species in commercial orchards. Predaceous mites were collected in commercial orchards primarily in the latter part of the growing season following cessation of spraying. In abandoned orchards, the stigmaeid Agistemus fleschneri Summers was the most abundant predaceous mite, with the phytoseiids Phytoseius macropilis (Banks) and Typhlodromus pomi (Parrott) also frequently collected. In abandoned orchards, predaceous mites were collected throughout the season and were generally more abundant.

The encyrtid wasp Epidinocarsis lopezi (De Santis) has been introduced into Africa as a biological control agent against the cassava mealybug Phenacoccus manihoti Matile-Ferrero. This host has a defense reaction against the immature parasitoid that involves encapsulation and melanization. Under laboratory conditions, 37.5% of once-stung cassava mealybugs had been parasitized, as indicated by eggs and larvae of the parasitoid in dissected hosts. Of these parasitized cassava mealybugs, 89.6% contained melanized particles (egg, partially melanized larva, internal host tissues, exoskeleton wound scars). Some of the parasitoid larvae were only partially melanized, and either freed themselves from the melanized capsule or else shed it at the next molt. By the 3rd day of their development only 12.5% were completely melanized. In cassava mealybugs with melanized host tissue but no living parasitoid, the survival of the host was not affected by the melanization. The mealybug itself sometimes shed black particles at the next molt and these were found attached to the cast skins. When superparasitized in the laboratory, 68.6% of twice-stung cassava mealybugs contained parasitoids. Mummies collected from a field experiment showed that melanization rates of mummies increased with increasing parasitization rates. Thus, melanization in the cassava mealybug was commonly triggered when E. lopezi oviposited, but this defense reaction was mostly ineffective, permitting the introduced parasitoid to be a successful biological control agent in Africa against the cassava mealybug, a major pest on this important food crop.

It is a commonplace entomological observation that each phytophagous insect is restricted in its feeding to a small fraction only of the plant species that grow in any area. This phenomenon is generally referred to as “host selection”. The ecological significance of host plant selection among insects is manifest principally in an effect on the geographical distribution of insect species since phytophagous insects can occur only where suitable host plants are available.

In the laboratory, second- and third-instar Plutella maculipennis (Curtis) larvae were about equally susceptible to parasitism by Diadegma insularis (Cresson) or by Microplitis plutellae Muesebeck. The fourth and last instar was less susceptible than the second and third. Larvae of the first instar, although usually within the tissues of the food plant, could be parasitized. Maximum progeny obtained from female parasites during a lifetime, with regularly renewed supplies of hosts, averaged 516 in D. insularis, and 232 in M. plutellae. Effectiveness of D. insularis among a given number of host larvae improved slightly, reaching 85/100 as cage size increased from 50 to 200 sq. in., and declined somewhat, from 124/200 to 94/200, when cage size was further increased from 200 to 1500 sq. in. In field cages of 1, 2, and 4 sq. yd, with 200 host larvae, single female D. insularis parasitized about 35, 20, and 7% of hosts respectively. With 50, 100, 200, and 400 host larvae in 200-sq.-in. cages, and one female per unit, average progeny of D. insularis were respectively 39, 70, 113, and 150; of M. plutellae, approximately the same. In competition, two females, one of each species, operating among the same lot of larval hosts, produced more total progeny than two of the same species. Increasing constant temperatures from 20° to 30° favoured D. insularis slightly, but viability and effectiveness of M. plutellae at 30° was reduced.

Collections of Amitus (Hymenoptera: Proctotrupoidea, Platygastridae) from the Western Hemisphere are referred to the following species: from Canada and the United States, A. aleurodinis Haldeman, A. granulosus n. sp., and A. gibbosus n. sp.; from Mexico and South America, A. spiniferus (Brethes), A. pigeanus n. sp., A. hesperidum Silvestri, and A. fuscipennis n. sp.

A lateral plate-like process on the male fourth antennal segment is regarded as a phenocline, characteristic of species or species groups.

Influence of temperature and moisture on black cutworm, Agrotis ipsilon (Hufnagel), development and reproduction was studied on field corn. The black cutworm spends portions of its life above and below soil, consequently influence of temperature and soil moisture and temperature and relative humidity (R.H.) was determined. Temperatures of 34°, 27°, and 20°C were used with 18%, 24%, and 30% soil moisture and with 40%, 60%, and 80% R.H. In addition, a treatment of 13 °C and 60% R.H. was included.

Temperature was the only factor influencing development of all stages, with 27°C the optimum temperature studied. Soil moisture did not influence larval development, but relative humidity affected the first five instars. Larvae required from 6 to 9 instars to complete development, with temperature and relative humidity affecting the number of molts. Head capsule measurements varied depending on the number of molts required for development. Fecundity was greatest at 27° and 20°C, and at 60% and 80% R.H. The optimum treatment for reproduction and adult survival was 20°C and 80% R.H. Many females failed to lay fertile eggs at 34° and 13°C.

This report deals with studies of the biology of 10 species of the genus Triatoma Laporte, all of which were collected in Argentina and reared in the Microbiology and Parasitology Institute of the School of Medicine, University of Buenos Aires.The specific purpose of the study was to determine, for each species, average values for number of eggs per female, proportion of eggs hatching, time required for hatching and for the development of each instar nymph, the longevity of female and male adults, and the length of egg-adult and egg–egg cycles.These studies extend the knowledge of the biology of vector species of Chagas’ disease and have been done in conjunction with studies of the geographical distribution of the insects.

This paper is one in a series on techniques used in estimating populations of various stages of the larch sawfly (Ives, 1955b; Ives and Prentice, 1958). This insect spends most of the year in cocoons in the soil beneath the host tree. The objective of accurate estimation of the cocoon population is to provide a basis for the evaluation of mortality factors affecting this stage. Two methods of estimation are considered in this paper. One is based on soil sampling (Part I) and the other on the number of cocoons formed in traps for falling larvae (Part 11).

Outbreak and declining populations of spruce budworm (Choristoneura fumiferana (Clem.)) were sampled extensively at three locations in New Brunswick, Canada, between 1982 and 1992 and were examined for the prevalence of granulosis and nuclear polyhedrosis viruses (Baculoviridae). Larvae, pupae, and adults were collected using a variety of methods. Spruce budworm nuclear polyhedrosis virus (CfMNPV) genomic DNA probes and wet-mount light microscopy were used to determine CfMNPV prevalence in 50 274 juvenile spruce budworms. Spruce budworm granulosis virus (ChfuGV) genomic DNA probes were used to determine the prevalence of ChfuGV in 25 703 of these same samples. The prevalence of both viruses was low, with ChfuGV and CfMNPV not found in more than 15% and 2%, respectively, of samples in any collection in a given year. Prevalence of ChfuGV was greatest in mid- to late June in sixth-instar larvae. Each virus was detected in only two of 2177 female moths and in none of the 420 male moths examined. In the entire collection, cytoplasmic polyhedrosis virus (Reoviridae) was detected in only two budworm larvae and entomopoxvirus (Poxviridae) was not detected in any.

Relatively little information concerning the cuticular hydrocarbon composition of aquatic insects is known. The cuticular hydrocarbons of the aquatic beetle Agabus anthracinus Mannerheim have been identified with the aid of a gas chromatograph coupled to a mass spectrometer. The cuticular hydrocarbon profile comprises n-alkanes (46.8%), n-alkenes (27.1%), and methylalkanes (25.9%) and is basically similar to that of terrestrial Coleoptera. However, the hydrocarbons of A. anthracinus differ in that (i) the shorter chain n-alkanes are present in higher proportion, (ii) there is a relatively lower abundance of methylalkanes, and (iii) the proportion of n-alkenes is significantly higher.

Investigations of the bionomics and populations of Cyzenis albicans (Fall.), in relation to its principal host, Operophtera brumata (L.), were carried out during 1962–1963 in two stands of red oak in Nova Scotia. C. albicans was well synchronized with its host and oviposited only on leaves damaged by the host or by other defoliators. C. albicans was found experimentally to develop in larvae of a native species, Operophtera bruceata (Hulst). The distributions per leaf cluster of parasite eggs and host larvae were of the negative binomial type and it sampling technique employing 12 leaf clusters per tree produced standard errors which varied between 18 and 33% of the mean for average densities of 12 to 2 eggs per cluster. Parasite eggs per leaf cluster and percentage parasitism increased as host density increased. An associated defoliator, Pseudexentera cressoniana Clem., because it apparently stimulated parasite oviposition but was not itself susceptible to parasitism, had a detrimental effect on the efficiency of the parasite.

Three cereal aphids, Rhopalosiphum padi (L.), Schizaphis graminum (Rondani), and Sitobion avenae (F.), invade wheat fields in the northern Great Plains each spring, and populations occasionally reach economic levels. The first objective of this study was to describe the spatial distribution of three species of cereal aphids infesting hard red spring wheat (Triticum aestivum L.). The second objective was to develop two sampling plans for cereal aphids using individual stems as the sampling unit, a sampling plan with fixed levels of precision and a sequential sampling decision plan based on total numbers of aphids present. Aphid population estimates were collected from 47 eastern North Dakota spring wheat fields during 1993–1995. The number of aphids per stem were counted on 100–350 stems per field. Taylor’s power law and Iwao’s patchiness regression were used to analyze the spatial distribution of the aphids. Rhopalosiphum padi and S. avenae exhibited an aggregated distribution, whereas S. graminum was distributed randomly in the field. Taylor’s power law provided a better fit to the data than Iwao’s patchiness regression. Sample size requirements for precision levels of 0.10, 0.15, and 0.25 were estimated with Taylor’s regression coefficients. Required sample sizes increased with decreased aphid populations and increased levels of precision. The two sampling plans presented should be useful for research on cereal aphid population dynamics and pest management decision making in spring wheat.