Preliminary Field Tests Using a Polyhedrosis Virus to Control the Alfalfa Caterpillar1

Further tests using a polyhedrosis virus to control the alfalfa caterpillar

“…To ascertain the possible practical value of distributing the virus artificially, four separate tests were conducted during the summer of 1948 (Steinhaus and Thompson, 1949) on plots situated in alfalfa fields in central California in the Westley-Patterson area (northwest portion of the San Joaquin Valley) . Comparable plots in the same fields were established as untreated controls.…”

“…This was accomplished during the summer of 1948. A preliminary report of the 1948 field tests has already been published by Steinhaus and Thompson (1949) and the next few paragraphs are-a brief recapitulation of this report.…”

“…Based on the-experience gained in the 1948 field tests (Steinhaus and Thompson, 1949), several changes and modifications were adopted at the start of 1949 field work. All caterpillar population samples were standardized at 2 uniform sweeps of the sweeping net.…”

The integration of chemical and biological control of the spotted alfalfa aphid: The integrated control concept

“…On the basis of his population counts, other conditions peculiar to each situation, and his knowledge of the ecology of the pests and their biological controls, the entomologist makes predictions as to the course of the population trends and advises as to when controls should be applied and what kind. For in stance, in the case of the alfalfa caterpillar, Colias philodice eurytheme, when economic thresholds are reached, the recommended procedure may involve immediate cutting of the hay crop without treatment, application of the polyhedrosis virus (Steinhaus and Thompson, 1949;Thompson and Steinhaus, 1950), or treatment with an insecticide. The course to be taken depends on the characteristics of the particular infestation (Smith and Allen, 1954).…”

The effects of disease on insect populations

“…Instead, it is based on the natural protective properties of the animal's anatomy, physiology, biochemistry, and genetic make-up. A discussion of the role of these factors in innate immunity has been presented elsewhere (for example, Redaelli, 1929 ;Paillot, 1933;Steinhaus, 1949) ; suffice it to remark here that although this type of immunity or resistance expresses itself in numerous ways, from so-called phylogenetic resistance to external mechanical defenses, the manner in which it actually functions in insect populations is known largely Hilgardia [Vol. 23,No.9 by inference and assumption.…”