. Bulletin. Natural history; Natural history. 534 Illinois Natihal Histokv Suhvey Bllletix. Chinch Bug- /9£3 ^evEPe MO DC a A T£ Fig. 28. Rlap of Illinois showing reported areas of damage to crops by chinch bugs in 1923, together with inches of rainfall in May (lower figures) and in June uipper figures) in each locality. by Thunias (ISi!)) that a dry May and June ami two dry siiniuicrs are essential to the development ot excessive minibers of these pests. Though they are apparently absent from large areas in spring, the small numbers which are jiresent in a gi\en area may develop rapidly if th
. Bulletin. Natural history; Natural history. 534 Illinois Natihal Histokv Suhvey Bllletix. Chinch Bug- /9£3 ^evEPe MO DC a A T£ Fig. 28. Rlap of Illinois showing reported areas of damage to crops by chinch bugs in 1923, together with inches of rainfall in May (lower figures) and in June uipper figures) in each locality. by Thunias (ISi!)) that a dry May and June ami two dry siiniuicrs are essential to the development ot excessive minibers of these pests. Though they are apparently absent from large areas in spring, the small numbers which are jiresent in a gi\en area may develop rapidly if the season is very favorable and may increase to enormous numbers by autumn, and enough of them may siuvive the winter to build up a population that will do a great deal of damage in the following year even if the weather then is adverse. The variation in vitality and fecundity referred to above is, howexer. a subject for the most careful investigation from a jihysiological \iewpoint. Their decline is jirobably. 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 Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
