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| Publication Type:
| Report |
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| Author(s): | Potter, D. A. |
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| Title: | Seasonal emergence and flight of northern and southern masked chafers in relation to air and soil temperatures and rainfall patterns |
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| Source: | Kentucky Turfgrass Research. 1981, p. 13-14. |
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| Publishing Information: | Lexington, KY: University of Kentucky, College of Agriculture, Cooperative Extension Service |
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| Keywords: | TIC Keywords: Cyclocephala borealis; Cyclocephala lurida; Insecticides; Soil temperature; Grubs; Life cycle; Insect control
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| Geographic Terms: | Kentucky |
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| Abstract/Contents: | Characterized the flight periods of northern and southern masked chafers, estimated the relative importance of each of these species in central Kentucky, and determined the optimum treatment dates for new-hatched white grubs. Flight activity of adult masked chafers was monitored continuously from May 15-Aug 30 during 1979-80, using standard blacklight traps. Traps were emptied either nightly or at least 3 times each week, and captured beetles were sorted and sexed. To determine a minimum temperature threshold for development of overwintering grubs, 3rd-instar larvae were dug from overwintering sites in early March and reared in pots at 6 different temperatures until pupation. Using the calculated base temperature, degree-day summations to the dates of 1st emergence, 50% flight, and 90% flight were computed for each species. The temperature threshold for pupation of overwintering grubs was determined experimentally as 10.8 degrees Celsius (51 degrees Fahrenheit). This means that spring soil temperatures must warm to 51 degress Fahrenheit before hibernation masked chafer grubs will become active and resume development toward adults. A table provides date of 1st, 50%, and 90% capture for both species in 1979 and 1980. Flight occurred 1-2 weeks earlier in the northern species. Both had finished laying by the third week of July. Since the eggs require 14-18 days for hatching, in a typical year virtually all will have hatched by early August. Based on these studies, the optimum treatment date for masked chafer grubs in Kentucky is Aug. 1-15, when the eggs have hatched and the young grubs are most vulnerable, but before the turf has been badly damaged. Flight patterns of the 2 species are close enough that they can be considered together for management purposes. First emergence of northern and southern masked chafers can be expected after degree-day accumulations of 500 and 585, respectively (based on centigrade air temperatures and a base of 10.8 degrees Celsius). Degree days are less useful for predicting dates of 50% or 90% flight. Once emergence has begun, nightly flight activity of masked chafers is greatest on nights following heavy rain. |
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| Language: | English |
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| References: | 0 |
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| Note: | Table |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Potter, D. A. 1981. Seasonal emergence and flight of northern and southern masked chafers in relation to air and soil temperatures and rainfall patterns. KY. Turfgrass Res. p. 13-14. |
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