Using Foliar and Planting-time Insecticides to Control Chinch Bugs in Grain Sorghum

Gerald Wilde and Terry Mlze Chinch bug infestations have been more widespread and intense in eastern Kansas in recent yea rs than since the outbreaks of the 1930's and 50's. Field insecticide tests in I 977 indicated that correctly applying foliar insecticides significantly reduces chinch bug numbers, and greenhouse tests suggested that some granular treatments at planting time will control chinch bugs on seedling sorghum, so tests were continued in 1978. In the first test, planted June 5, a granular application at planting time was evaluated 8 and 21 days later (Table 1). The most effective treatment on day 8 (June 13) was an in-furrow treatment of carbofu ran. No band treatments gave good control. At 21 days (June 26) carbofuran in-furrow or a band gave some control, but left some chinch bugs surviving on all plants. In th'!l second test, planted June 29, planting-time applications were evaluated 14 days later (Table 2). Infurrow treatments of carbofuran and bands of or phorate significantly reduced chinch bug numbers. A 1.2-inch rain 1 I days after planting probably accounted for the effectiveness of the band treatments in the second test. 1. Mention of a compound and results do not constitute a recommendation by the Kansas Agricultural Experiment Station or the Kansas Cooperative Extension Service.


MARCH 1979
Using Foliar and Planting-t ime Insecticide s to Control Chinch Bugs in Grain Sorghum 1

Gerald Wilde and Terry Mlze
Chinch bug infestations have been more widespread and intense in eastern Kansas in recent yea rs than since the outbreaks of the 1930's and 50's. Field insecticide tests in I 977 indicated that correctly applying foliar insecticides significantly reduces chinch bug numbers, and greenhouse tests suggested that some granular treatments at planting time will control chinch bugs on seedling sorghum, so tests were continued in 1978.
In the first test, planted June 5, a granular application at pla nting time was evaluated 8 and 21 days later ( Table 1). The most effective treatment on day 8 (June 13) was an in-furrow treatment of ca rbofu ran. No band treatments gave good control. At 21 days (June 26) carbofuran in-furrow or a band gave some control, but left some chinch bugs surviving on all plants.
In th'!l second test, planted June 29, planting-time applications were evaluated 14 days later (Table 2). Infurrow treatments of carbofuran and bands of or phorate significantly reduced chinch bug numbers. A 1.2-inch rain 1 I d ays after planting probably accounted for the effectiveness of the band treatments in the second test.
1. Mention of a compound and results do not constitute a recommendati on by the Kansas Agricultural Experiment Station or the Kansas Cooperative Extension Service.  Of the granular tests, the carbofuran in-furrow treatment is registered for use on sorghum for ch in'ch bug control. Both carbofuran and phorate band treatments are registe red for use on so rghum for greenbug contro l, but not fo r chinch bugs. Disu lfoton, reg iste re d as a band treatment for g reenbug control, does not affect chinch bugs. Phorate should not be applie d in-furrow a t pl anting time because of its phytotoxicity .

AGRICULTU RAL EXPERIMEN T STATION
Foliar a pplications of carbaryl, ca rbofuran, and e ndrin were tested on seedling sorghums, though endrin is not registered for sorghum crops. The other two are registe red for chinch bug control. We included it as a chlorinated hydrocarbon to which control with newer inse cti· cides can be compared. The fo liar sprays we re applied with a one-nozzle hand sprayer del ivering 16 gal. of water per acre. Results of two tests at Abilene (Table  3} and one test at Manhattan (Ta ble 4) indicate th at all those insecticides significantly reduced ch inch bug num- bers. ' But their residual poison does not extend more than 3 days, so chinch bugs migrating into a sorghum field could make repeated applications necessary.
The :most important point in controlling chinch bugs with foliar sprays is to use drop nozzles or other methods to direct sprays to the base of plants where bugs congregate and to use as much water as possible, preferably at least 16 to 20 gallons per acre.
Most Important In applying carbofuran at planting time is application In the seed furrow, which is more effective than the b and treatments because it does not require a rain for treatment to control ch inch bugs.