. Chenilles attaquant les tomates. Chenilles ; les tomates. 32 Université de Californie-Experiment Station CONTROL Au début de la saison où les vignes sont petites, les vers peuvent être par- ment tenu à vérifier à la main-picking, mais aussi les vignes poussent et l'infestation augmente, il peut devenir nécessaire à la poussière les champs de tomates avec un insecticide. En 1936 une forte infestation des hornworms est produite dans la zone d'expérimentation sur Union Island. Au départ, nous avons choisi le vers, mais d'ici le 17 juillet l'infestation est devenu si grave que de poussière. Fig. 19.-A, de la pupe, ver Protoparce tabac quin- quemaculata

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. Caterpillars attacking tomatoes. Caterpillars; Tomatoes. 32 University of California—Experiment Station CONTROL Early in the season when the vines are small, the worms can be par- tially held in check by hand-picking, but as the vines grow and the infestation increases, it may become necessary to dust the tomato fields with an insecticide. In 1936 a heavy infestation of hornworms occurred in the experimental area on Union Island. At first we hand-picked the worms, but by July 17 the infestation became so serious that dusting. Fig. 19.—A, Pupa of the tobacco worm, Protoparce quin- quemaculata (Haw.), B, pupa of the tomato worm, P. sexta (Johan.), in its cell. The distinguishing character that separates the two species is the sheathed proboscis, which is longer in the tomato worm. (From Ext. Cir. 99.) became necessary. The damage was checked, but by August 24, injury was increasing and the area was therefore dusted for a second time. This dusting was sufficient to control the pest, although on September 25 the experimental area was again dusted because a corn-earworm infestation was developing. The materials used were calcium arsenate, lead arsenate, cryolite, barium fluosilicate, and sodium nuosilicate. The arrangement of the plots and the composition of the insecticides were the same as used for the corn earworm for 1936 (see p. 12 and fig. 9). At various intervals, the plots were examined for hornworms and in- jured plants. No note was made of the degree of injury, but the total number of damaged plants and the number of worms found in each plot were recorded. In making the surveys, a buffer row was left around each. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Michelbacher, A. E. (Abe Ezra), 1899-1991; Essig, E. O. (Edward Oliver), b. 1884. Berkeley, Cal. : Agricultural Experiment Statio

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