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NEW MATERIALS FOR CONTROL OF Tl-IE STRAWBERRY CROWN BORER
P. o. Ritcherl `
Widespread injury by the strawberry crown borer during the late summer of 1948
in the jackson Purchase, the Bowling Green Frank1in, and the jefferson County berry grow--
ing areas of Kentucky has prompted further studies on control measures Since growers
have made little use of methyl bromide fumigation or poison baits, the control methods
recommended in Ky. Agr Expt. Sta, Bul. 468, attention has been turned to newer insecti
Laboratory- test.- In April 1949, several hundred over ~wintering adult crown
borers were collected by W. D Armstrong and the writer from a borer -ruined straw -
berry patch near Sharpe, Kentucky. From Z to 13 adults were found on or about each plant.
These adults were taken to Lexington, where laboratory tests were made with a number of -
the newer organic insecticides. Each material was dusted evenly over 4 potted straw-
berry plants, using a hand duster. Ten crown borer adults were placed at the base of each
t plant and confined by means of a cylindrical, 16 mesh, galvanized wire cage placed over
Results are summarized in Table 1.. Of the materials tested, 1 and 2. percent
Parathion, 5 percent Chlordane, and 20 percent Toxaphene dust gave excellent control.
) Poor results were obtained when benzene hexachloride (odorless) dusts were used. i
They contained l 1/Z percent and 3 percent of the gamma isomer, each with 5 per-
cent DDT dust. Fair results were obtained with DDT spray (1 lb actual) and a dust con-
taining 2 l/Z percent compound 118.
Parathion was the quickest acting of the materials tested, killing most of the crown Qi-
borer adults in 3 days. Where Chlordane and Toxaphene were used, many affected beetles
continued to move their appendages for 5 or 6 days but none recovered. Beetles affected by
benzene hexachloride, however, often recovered and proceeded to feed normally.
V Field tgisi On April 20 a newly set strawberry patch was located in jefferson county
which was being invaded by crown borer adults from adjacent old patches, one of which had
been plowed under several months previously. Two plots each 140 feet long and 4 rows wide
. were dusted, one with 5 percent Chlordane dust and one with Z0 percent Toxaphene dust,
using a knapsack, continous duster. The rest of the patch was left untreated.
. Five days later, dead or dying crown borer adults were fairly common about treat-
ed plants, especially on the side of the new patch closest to the old patches. Some beetles
were lying beneath the leaves near the crowns of the plants; others were in depressions
in the soil surface, in some cases out in the open a foot or more away from plants. Many
live beetles were still present in the untreated area.
12i_s_g1_ss_iogn; These tests indicate that several of the newer insecticides can be
A used to kill adult crown borers. Since new patches usually become infested by adults
crawling from nearby old patches, the best method of control appears to be one thorough
N 'l""Since Aug. 1, 1949 with North Carolina State College, Raleigh, N.C.