The number of the birch casebearer larvae, Coleophora fuscedinella Zeller, within white birch crowns, Betula papyrifera Marsh., decreased 70% from overwintered survivors to about 50% pupae in the population. Within a crown, the highest number occurred in the outer shell and lowest in the inner. Casebearer numbers, weighted by the number of leaf clusters, were highest in the inner shell and lowest in the outer. Among crown quarters, both unweighted and weighted numbers were generally highest in the middle two crown quarters, lowest in the bottom quarter, and variable in the top quarter.

Peaks in immigration and emigration of larvae among crown strata occurred first when third and again when fourth instar larvae were most abundant. Immigration consisted only of intra-tree crawling, but emigration consisted of intra-tree crawling, removal by predation, and larvae leaving the tree to pupate on ground vegetation.

Regression equations of per cent defoliation of white birch stands, Betula papyrifera Marsh., to birch casebearer, Coleophora fuscedinella Zeller, eggs or larvae had precisions (standard error of the estimate, b) of about 20% of the estimate. Although log-transformation of counts stabilized the variance, it did not increase the precision of the equations. Precision of regression estimates based on data from whole-stratum sample units differed little from that from only four mid-crown branches. The latter sample universe is smaller and more rapidly examined.

Laboratory and field studies indicate that differences in gypsy moth egg mass characteristics can be related to larval density and natural diet. Egg mass characteristics are valuable indices of population quality as well as future population levels. Laboratory crowding reduced number of eggs/mass but did not affect egg size. Field collected egg masses from various population levels in Massachusetts also varied in egg number/mass, but egg size could not be directly correlated to density. Laboratory rearing of larvae on several natural diets produced differences in both egg number and size. Maple diets produced egg masses with fewer, smaller eggs, as compared with oak diets. Field collected egg masses also varied in mean egg size, according to host tree species. Thus, forest composition may directly affect the quality of gypsy moth populations, as well as numerical levels. Increasing density could affect egg size indirectly, by forcing gypsy moth larvae to feed on unfavorable host foliage.

Experiments were designed to determine the actual number of spores and crystals of Bacillus thuringiensis (B.t.) and of nuclear polyhedral virus and entomopoxvirus deposited at ground level per unit area and to determine any change in spore:crystal ration following aerial application in forested plots.

The results indicate that: (1) The estimation of B.t. aerial spray deposits by the commonly used agar plate method grossly underestimates the deposit rates of active ingredient. The tracer dye method more accurately estimates deposit rates for both B.t. and entomopathogenic viruses. As a dye 0.1% Erio Acid Red XB is recommended. (2) The relationship between drop size and the number of spores and crystals or virus inclusion bodies/drop is curvilinear. This relationship probably holds true regardless of spray volume rate. All visible spray deposits at ground level contained some active ingredient. (3) With B.t. sprays the sporexrystal ratio emitted from the aircraft is not changed upon target impact.

Population data collected from 132 trees during a 3-year period were used to simulate spots of K trees (1≤ k ≤ 50) infested by the attacking adult stage of Dendroctonus frontalis Zimmerman. The total number of beetles on the K trees was then estimated by sampling k trees (1≤ k ≤ 10). The k trees were chosen at random and by selecting those of largest diameter and largest infested area. Within-tree populations were estimated at two levels of precision and within-spot populations were then estimated by scaling the sum of the k within-tree estimates according to the proportion of the tree numbers, tree diameters, or infested phloem areas included in the sample. The various combinations of tree selection, within-tree precision, and scaling produced 10 procedures which were evaluated for bias, precision, and cost as estimators of within-spot populations. Bias was calculated as the mean of the proportional errors in estimating the true numbers, and the standard deviation of the proportional errors was used as a measure of precision.

The procedures in which trees were randomly selected provided unbiased estimates of the within-spot populations. Selecting the largest trees tended to overestimate the true number with the bias diminishing to zero as k → K. However, separate analyses of trees sampled on the same date within actual spots showed no reason to reject the hypothesis of no difference in beetle density (insects/diameter and insects/area) between the largest and smallest trees.

When k = K = 1, the precision of all within-spot estimators was equivalent to the precision of the within-tree estimate. For larger k = K, the precision improved approximately as √(K). No attempt was made to derive functional relationships of precision for k < K. For each procedure, precision improved as k → K. Sampling the k trees at two sample heights (3.5 and 6.5 m, 4–100 cm2 disks/height) was more precise than single level sampling (4 disks at 5 m), but equally precise estimates could be obtained by single level sampling of just one or two additional trees in the spot. Random selection of the k trees with scaling by the number of infested trees was the least precise of the estimating procedures; scaling by diameter and by infested surface area increased the precision. Best precision was obtained by selecting the k trees of greatest infested phloem area, but selecting the largest diameter trees was nearly as precise. The least costly procedure for obtaining a desired level of precision consists of selecting the k trees of largest diameter and extracting 4 disks/tree at 5 m.

An abdominal tip extract of female bertha armyworm moths, Mamestra configurata (Walker), was found to contain two sex pheromone components. One corresponded to (Z)-11-hexadecen-1-ol acetate, previously identified from this source, and the other to a tetradecen-1-ol acetate, identified by gas chromatography – mass spectrometry. Data obtained from the EAG profile of isomeric tetradecen-1-ol acetates indicated the active component to be (Z)-9-tetradecen-1-ol acetate. Neither of these two acetates was by itself attractive to males in field tests; however, mixtures were attractive, with the best attraction occurring with a C16:C14 acetate ratio of about 19:1.

The following new odontiine taxa are described: Clupeosoma cicatricale, Sumatra; C. margarisemale, Java; C. microthyrale, Sabah; Hydrorybina fulvescens, Sumatra; Hemiscopis intermedialis, Soemba; Platynoorda, and its type-species P. atrivittalis, Sabah; Porphyronoorda, and its type-species P. decumbens, S. India; Gononoorda, its type-species G. neervoorti, Java; also G. jacobsoni, Sumatra. Hydrorybina Hampson is removed from the synonymy of Clupeosoma Snellen, and is redefined. In addition to the type-species, H. polusalis (Walker), and the new species H. fulvescens, the genus includes two species, Anemosa pryeri Butler and Clupeosoma violascens Hampson, transferred as new combinations from Clupeosoma. Syllythria bicolor Moore, placed first in Hydrorybina then in Clupeosoma by Hampson, is considered probably odontiine but probably not a member of either of those genera. It is left in Clupeosoma pending further investigation. Eurycreon? rubralis Warren is removed from the synonymy of C. bicolor and is transferred to the subfamily Pyraustinae as Pyrausta rubralis (Warren), n. comb. The relationship of Hydrorybina to Hemiscopis Warren is pointed out, and differential characters are given. Micromania Swinhoe, with type-species M. stigmatalis Swinhoe, is removed from the synonymy of Hemiscopis and is transferred to the subfamily Nymphulinae in the vicinity of Paracymoriza Warren, which is removed from the synonymy of Parthenodes Guenée. Noorda moringae Tams and N. trimaculalis Amsel are transferred to Epinoorda Rebel as new combinations.

A general population model for cotton growth and development is presented. The model captures the essential properties of the biological processes, and is sufficiently flexible to the incorporation of complex physiological and behavioral characteristics. The model has been used successfully to simulate the growth and development of Acala SJ-II cotton in California. The mathematical framework for coupling plants and herbivores has been presented, and the biological implications of their damage to the plant examined in a very general way.

A method is described for partitioning normal plant fruit shedding losses from those caused by the pest Lygus hesperus Knight. The relationship between age of bug and its damaged rate per day degree was determined, and used to assess the impact of various lygus population levels on crop development and yield. A simulation model for lygus phenology and population dynamics is reported.

The diel periodicity of pupation and emergence was studied in Culiseta inornata (Williston) under field conditions in the Lower Sonoran Desert of southern California. Floating isolation units were employed for observation of these two phenomena over an 8-day study period. Both male and female pharate pupae exhibited a diel periodicity of pupation. Two daily modes were apparent for this process; the first, of lesser amplitude at around 0400 h, and the second, main peak, near 1600 h daily (sunrise: 0635 h, sunset: 1559 h). Distinct diel periodicity of emergence was evident for both males and females of Cs. inornata, with the peak more pronounced for females. For both sexes, a single combined peak of emergence activity occurred daily at around 1600 h.

The diel periodicity of emergence correlated significantly with fluctuations in water temperature. Other environmental conditions such as solar radiation, cloud cover, windspeed, and air temperature exerted no observable effect on pupation and emergence activity.

Field testing of a large number of synthetic compounds and two-component combinations thereof revealed an attractant for the adult males of Leucania commoides Guenée. Several three-component combinations were tested and the largest numbers of L. commoides males were attracted to Z-9-tetradecen-1-yl acetate, Z-11-hexadecen-1-yl acetate, and Z-11-hexadecen-1-ol in ratios of 4:4:1 to 10:5:2. The attraction of this species was inhibited by Z-9-tetradecen- 1-ol.

Manipulation of individual first instar larvae of the oriental fruit moth (OFM) has been successful using a sable hair (Fisher and Menzies 1976). However, when large numbers of larvae must be treated quickly and held for a long time, they cannot be handled singly. Also, larvae exposed to insecticides, even for short periods, are hard to retain on a substratum for observation.

The presence of female-produced sex pheromones in diaspidid scales has been known for several years, and was recently documented for the San Jose scale, Quadraspidiotus perniciosus (Comstock) (Rice 1974). This paper reports the results of 3 years of seasonal monitoring for male San Jose scale in an attempt to determine how and when this pheromone might be used as a monitoring technique in pest management programs in deciduous fruit orchards. These studies were conducted at the San Joaquin Valley Agricultural Research Center near Parlier, Fresno County, Calif.

It is difficult to estimate numbers of small active insects, particularly predators, in fruit-tree canopies because of the frequent and rapid movement of these species. The conventional method of sampling such populations requires tapping the branch to dislodge the insects which fall to a cloth tray from which they are recovered and counted. However, many species take to flight very rapidly and escape before identification is possible. A sampling method was required which would rapidly enclose a volume of the canopy without disturbing the resident population, thereby eliminating inaccuracies in the sample obtained. This note describes a remotely operated mechanical trap which can be placed on a limb in the tree canopy. The insects thus trapped can be immobilized, counted, and identified.