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Looking Ahead

Forages & Grains

Corn

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Degree Days

Vegetables
Volume 61 Number 4 Date 05/19/2016


IMPORTED CABBAGEWORM - Larvae are emerging in advanced southern and western areas of the state. Cabbageworms chew large, irregular holes in leaves, bore into heads, and drop brown fecal pellets that contaminate the marketed product. Cole crops can tolerate considerable defoliation at the thinning or transplanting stages, but frequent sampling is recommended to assess populations. The biological insecticide, Bacillus thuringiensis (Bt), is effective against early-instar caterpillars and is an OMRI-approved control for infestations affecting 30% or more of plants during the transplant to cupping stages. Treatments should be carefully targeted to avoid disrupting natural enemies.

ONION MAGGOT - Peak emergence is anticipated next week in the southwestern, south-central and west-central counties, following the accumulation of 680 degree days (simple base 40°F). Flies of the spring generation are often the most damaging. Rotating this year's plantings as far away as possible from last year's onions is perhaps the most basic approach to onion maggot control. Preventative soil insecticides may be considered if 5-10% of last year's crop was damaged by onion maggot.

-- Krista Hamilton, DATCP Entomologist