Emergence of Adult Hessian Flies (Diptera: Cecidomyiidae) From Overwintered Puparia

(excerpt) The Hessian fly, Mayetiola destructor (Say), is a pest of wheat and more rarely barley and rye. The fly usually has two generations per year in Michigan, one in the spring and the other in the fall. The summer and winter are spent as small, hard, black puparia (called flax seeds ) in the culms of the host small grains and grasses. Farmers very early found that fly damage could be avoided by planting their winter grains late in the season. Studies made early in this century found that the earliest date for planting to avoid the fly (the fly-free dates ) could be predicted and these dates have become an accepted practice

Diurnal Sampling of the Insect Complex of Alfalfa

The appearance of the alfalfa weevil, Hypera postica (Gyllenhal), in Michigan in 1966 (Dowdy 1966) necessitated intensive testing of methods for its control. There is a con~plex of insect pests in alfalfa, and the effects of control measures for alfalfa weevil on these other pests needed to be considered. An efficient sampling method that measures as many species of the complex as possible was needed. Preliminary tests of the author showed that 20 sweeps with an insect net of 15 in. diam., a standard sampling tool for alfalfa, was satisfactory for sampling the insect complex. A means of separating the insects from the plant debris collected in the net, and information on the time of day that samples should be made were needed. Satisfactory answers to these two problems were found and are summarized here

An Inventory of Stored Grain Insects in Michigan

(excerpt) The problems with insects in commercial and farm-stored corn, small grains, dry beans, and soybeans are reduced to a minimum by Michigan\u27s cool climate and usually short period of storage (Ruppel, 1976). Yet insects still infest scattered bins of grain in the state. The incidence of stored grain problems has increased over the past few years. This increase is attributed to an increase in farm storage, often under poor conditions. Poor ventilation of the grains that causes an increase in moisture content at the surface of the grains has been the most common problem. The result has been a flush of problems with what are considered secondary pests; that is, those species that usually can increase only in grains that are in poor condition

Addendum to the Inventory of Stored Grain Insects in Michigan

Additional species of stored grain insects have been found in Michigan since the inventory of such pests was published (Ruppel 1977). The additional species were primarily found through a study of insects in county elevators (Russell 1980) and through examinations of infested grains submitted for identification. The names of these insects are given in Table 1. The brown spider beetle and murmidius beetle were found in infested small grains, the European grain moth was found in stored soybeans and in elevator trash. and the others were found in elevator trash

Some Observations on Insecticide Resistance

A model for development of resistance to an insecticide in an insect population is presented. The rate of development of resistance increased with increases in the proportion of the breeding population exposed to the insecticide and with increases in the survival from exposure to the insecticide. Restricting application of insecticides to an only if needed basis and, within limits, dosages that assure minimal survival of the exposed insects are suggested as means of impeding resistance to insecticides. The huge gene pools represented by the large populations of pest species are assumed to maintain insecticide resistance as a continuing problem in crop protection

An Assymmetrical Gynandromorph of Cerotoma Facialis (Coleoptera: Celerucidae)

Excerpt: There is a marked sexual dimorphism in beetles of the genus Cerotoma. The female has cylindrical antennal segments; a smoothly convex frons that lacks lobes and subantennal pores, and that is usually dark in color; relatively slender protibia with spurs; nearly cylindrical protarsi 1 without pads; and is somewhat larger than the maIe. The male has depressed and enlarged antennal segments 11 1 and 1V; a white, concave frons with various lobes, enlongate setae, and subantennal pores (a pair of pit-like openings underneath the dorsal lobe); rather swollen protibia without spurs; and enlarged protarsi 1 with ventral pads. Only males of Nearctic C. trifurcata (Forster) lack the modified antennae and the concave, lobed faces characteristic of all of the other Neotropical species of the genus. Unfortunately, C. trifurcata is the genotype of Cerotoma. My examination of several thousand specimens of Cerotoma for a study of variation in the genus has disclosed only one specimen that shows mixed secondary sexual characteristics. This is one of a series of C. facialis facialis Erichson collected from cowpea (Vigna siniensis) near Palmira, Valle de Cauca, Colombia, on 5 February 1960 by agronomist Eduardo Idrobo. The specimen has all black (rather than tan to dark brown) markings, a clear (one or more spots absent) elytral pattern, and a commissural suture that is 3.65 mm long. The markings and pattern are common in the deme of this species from this region. The length is small for a female but near average for a male of this deme for this season of the year

KNOWLEDGE GAPS FACING SMALLER FIRMS IN INTERNATIONAL AGRICULTURAL PRODUCT MARKETING

Knowledge gaps facing smaller firms in the U.S. food processing and distribution industries are discussed in the context of export decisions which these firms must make. The paper focuses on resources available for export assistance to smaller firms. It is argued that much of the assistance available to smaller firms is targeted to logistical problems facing all exporting firms. Less help is available as firms seek assistance in specific market research and product promotion. It is in these areas that land grant universities and federally funded Centers may be the most helpful resources available to smaller firms considering international marketing activities.International Relations/Trade, Marketing,

INFORMATION IMPACTS AND DETERMINANTS OF INFORMATION SELECTION: AN EXPERIMENTAL APPROACH

Laboratory experimentation was used to assess the impacts of information disclosure in imperfect markets. A dual oligopoly market structure was designed with contract information disclosed to subjects under three treatments: no, partial, and full disclosure. Regression analysis revealed some increase in selling price with full information disclosure, but no discernable effects on negotiated prices with partial disclosure. Alternative specifications showed large traders earning significantly lower profits, and information on large traders significantly beneficial to both buyers and sellers. Probit analysis of information selection determinants revealed no significant economic content in trader requests for information under partial disclosure.Marketing,

TRANSITION, TRANSFORMATION, AND TURMOIL: GLOBAL ECONOMIC IMPACTS ON U.S. FOOD EXPORTS

International Relations/Trade,

COTTON EXPORTS: ANALYSIS OF THE RELATIONSHIPS BETWEEN SALES AND SHIPMENTS

Relationships between cotton export sales and export shipments are examined, and a quarter-specific lag structure is estimated. Two econometric systems are estimated, one employing export shipments and the other using export sales. Results indicate that sales are more sensitive to changes in economic variables than shipments and that stocks net of outstanding export sales are more responsive to price and interest rate changes than gross stocks. Sales and shipments are different variables and cannot substitute for one another in econometric modelling. Use of export sales data should be considered in estimation of export demand and stock demand parameters.International Relations/Trade,