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We hypothesized that the ♀ boll weevil, Anthonomus grandis Boheman, does not discriminate against squares in which an egg has previously been oviposited. We call this the non-discrimination hypothesis. The objective of this study was to compare the observed distribution of single and multiple eggs/square over a range of infestation levels (0–100%) with theoretical values based on our hypothesis. We observed 28,750 squares and classified 22,526 oviposition punctures in yr 1 and 6500 squares and 3549 oviposition punctures in yr 2. Our data support the non-discrimination hypothesis—the ♀ boll weevil did not detect squares containing an egg and did not discriminate against squares containing an egg. Large samples such as these allow a statistical approach to an understanding of some aspects of insect behavior that can not be obtained from observations of a small sample or of a small number of samples.

The temperature of a thin turbid layer above the ground is expressed as a function of time by considering the processes of nocturnal radiation and eddy conduction. It is found that under certain conditions the layer will cool until the lapse rate below the turbid layer becomes unstable. It is suggested that vertical mixing then may transform the thin layer into a thick layer extending to the ground. At the same time increased stability above the turbid layer may result in a sharply defined upper boundary. The temperature distribution in a thick turbid layer is found to depend on the free-air and ground temperatures (treated as constants), the infra-red absorptivity of the layer, and the eddy conductivities within and above the layer. If certain critical conditions are satisfied, the lapse rate within the turbid layer will become unstable and the lapse rate within the non-turbid air will become stable. Observations of the vertical temperature distribution before and after fog formation support thi...

When quercetin, rutin, tannin, and gossypol were mixed in artificial adult and larval diets and fed to boll weevils, Anthonomus grandis Boheman, gossypol at 1.65 and 2.65% dry weight in the adult diet plugs caused a statistically significant increase in feeding, and levels of 1.15–2.15% significantly increased oviposition. Feeding was also increased at all other levels though not significantly beyond the base level of 0.15%. Gossypol, incorporated into larval diets in concentrations of 2.0–3.5%, significantly reduced the weight of emerging weevils, but 3.5% was required before the production of adults was significantly reduced. Quercetin did not significantly reduce feeding or oviposition. At levels of 0.1–0.6%, it increased the weight of emerging weevils, but at all other levels weight was not significantly affected. Tannin and rutin at levels of 0–1.0% did not significantly increase or decrease feeding. Tannin reduced weevil weight significantly at 0.2, 0.6, 0.8, and 1.0% levels; rutin at levels of 0.1–1.0% did not influence the weights of adult weevils at eclosion.

A large portion of the world's germ plasm of cotton has been screened at the USDA Boll Weevil Research Laboratory, State College, Mississippi during the period 1962–68 utilizing developed techniques. An oviposition suppression factor causing 25–40% reduction in number of eggs laid by the weevil has been found in Gossypium barbadense and successfully moved into upland cotton, G. hirsutum. Two years field data with frego cottons indicate that the frego character contributes a significant degree of non-preference for egg laying by the boll weevil under field conditions. The frego character is currently being combined with selected lines of G. hirsutum carrying the oviposition suppression factor. A seedling screening technique utilizing field cages and greenhouse sand flats has been shown to have significant value in screening for individual resistant plants within a commercial variety. A number of selections with 25% or more resistance to oviposition are under extensive investigation. A number of biologically active materials have been detected in the cotton plant and other hosts of the boll weevil which significantly influences feeding stimulation, feeding deterrency, repellency and attractancy of the weevil to its hosts. A highly active square abscission factor has been detected and extracted successfully from 2nd and 3rd instar larvae. The material injected into cotton squares causes 95% abscission of squares within 48–60 hours. ZUSAMMENFASSUNG RESISTENZ- UND ANFALLIGKEITSFAKTOREN DER BAUMWOLLE UND ANDERER WIRTSPFLANZEN GEGENUBER DEM BAUMWOLLKAPSELKAFER, ANTHONOMUS GRANDIS Ein groser Teil des Weltsortiments der Baumwolle wurde in den Jahren 1962–68 im USA-Baumwollkafer-Institut der Staatshochschule von Mississippi mit modernen Methoden getestet. Ein die Eiablage unterdruckender Faktor, der die Anzahl der abgelegten Eier um 25–40% herabsetzt, wurde bei Gossypium barbadense gefunden und erfolgreich in Hochland-Baumwolle, G. hirsutum, eingekreuzt. Zweijahrige Erfahrungen mit “frego”-Baumwolle weisen darauf hin, das das “frego”-Merkmal unter Feldbedingungen in einem signifikanten Ausmase zur Nonpraferenz fur die eierablegenden Kafer beitragt. Das “frego”-Merkmal wird laufend mit selektierten Linien von G. hirsutum kombiniert, die den Faktor fur Eiablage-Unterdruckung tragen. Eine Samlings-Prufungstechnik, die Feldkafige und Gewachshaus-Sandbeete benutzt, hatte nachweislich signifikanten Wert fur die Auslese resistenter Einzelpflanzen innerhalb einer Handelssorte. Eine Anzahl Selektionslinien mit 25 oder mehr Prozent Eiablage-Resistenz wird intensiv gepruft. Eine Anzahl biologisch aktiven Materials wurde bei Baumwolle und anderen Wirtspflanzen entdeckt, das Frasstimulation, Frasabschreckung, Repellenz und Attraktanz der Kafer in bezug auf ihre Wirte signifikant beeinflust. Ein hochaktiver Kapsel-Abwurf-Faktor wurde entdeckt und erfolgreich aus Larven des 2. und 3. Stadiums extrahiert. In Baumwollkapseln injiziert, verursachte dieses Material innerhalb 48–60 Stunden Abwurf von 95% der Kapseln.

Azinphosmethyl and methyl parathion applied at 0.125 pound per acre left greater deposits and caused higher mortality of Anthonomus grandis Boheman on frego than on normal bract cotton squares when: (1) weevils were caged in the field on the 2 types of cotton, (2) weevils were placed in 1-pint cartons with squares removed from the plant after spraying, and (3) when weevils were placed in cartons with squares sprayed after being picked from the plant. These results were confirmed by recovery of approximately 7 times the amount of residue from frego than from normal bract buds sprayed with methyl parathion.

A greenhouse seedling-selection technique was developed for mass screening seedling cotton, Gossypium sp., for resistance to Tetranychus urticae Koch. The salient procedures were mass rearing the two spotted spider mite on bean cotyledons for a constant source of mites, standardized greenhouse manipulation of plants, a plant-damage index for rating mite injury, and use of a standard variety for comparison of varietal resistance. The greenhouse seedling rating agreed with field rating and required Jess time (30 vs. 60 days). Fecundity was not a reliable indicator of resistance.

The temperature structure of Post Pond, a small (46.6 hectares), mid- latitude, dimictic lake in west-central New Hampshire, was studied during autumn, winter and spring of 1968-1969. The lake was instrumented over its maximum depth (11.7 m) with a string of 24 thermocouples which recorded hourly temperatures. Temperatures in 9 m of sediments underlying the lake were measured with a thermistor probe. Secondary and tertiary thermocline development in the epilimnion occurred during short warming periods in the early autumn. The autumn overturn lasted 25 days, whereas the spring overturn lasted only 4 days. The entire lake mixed isothermally in the autumn to 3.2C. During the period of ice cover, the lower 5 m of water gained approximately 51.5 cal/sq cm, which was supplied by stored heat in the bottom sediments. A steady-state thermal gradient of 0.07C/m was found for the deeper sediments underlying the lake during ice cover. Late winter cooling of bottom water under the ice cover may be the result of snowmelt in areas adjacent to the lake causing activation of groundwater influx. Melting of the clear ice portion of the ice cover was primarily the result of heat supplied to the lake from snowmelt water, and occurred on the underside of the ice sheet. Thermal instability of the water mass persisted for 9 days during peak snowmelt runoff; this can be partially explained by an increase in dissolved solids with depth.