Pest Control - 73
 

 

 

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Project Leader and Principal UC Investigators

A.A. Grigarick, Protection of Rice from Invertebrate Field Pests (RP3)

R.K. Washino

M.O. Way

C.K. Fukushima

R.P. Meyer

J.J. Knabke

C.L. Clement

M.D. Morse, CCRRF Variety Improvement

H.L. Carnahan

S.W. Johnson

S.T. Tseng

 

þ CHEMICALS VS. WEEVILS

Bux and carbofuran (furadan) as liquids showed no real advantage over granules when used in combination with liquid and dry formulations of herbicides and fertilizers.

Carbofuran (probably to be registered as a 5% granule in '74) will cover more acres per plane load. Bux should not be applied to water, because of registration restrictions and danger to fish. Both carbofuran and Bux were effective as preflood treatments even when applied to soil that had rice straw residues incorporated for the past 3 years. (RP3)

PESTS AND STRAW RESIDUE

Over 40 common species of aquatic animals were found to be neither repressed not encouraged by recommended methods of residue incorporation in rice fields. (RP3)

WEEVIL DAMAGE MEASURED

When rice was deliberately infested as it emerged from the water, resulting weevil larvae populations of 11 and 17 per plant resulted in grain losses of 20 to 44%. Like infestations administered only 2 weeks later gave respective grain losses of only 8 and 14%, indicating that susceptibility to weevil injury may decrease with plant age. (RP3)

RESISTANCE TO WEEVILS IS RARE

Plant resistance to water weevils has not proved easy to find. Resistance sufficient to justify further testing was found in only 7 of thousands of varieties evaluated. (CCRRF)

Fortunately, new varieties should not pose greater problems with weevils, for yield losses due to weevil injury proved similar in tests of Colusa, Cal-rose, Caloro, CS-M3, and CS-S4. (RP3)

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