home Susbcribe About Us Contacts Past Issues Print this issue


Looking Ahead

Forages & Grains

Corn

Soybeans

Fruits

Vegetables

Nursery & Forest

Degree Days

Looking Ahead
Volume 61 Number 19 Date 12/08/2016

PEST HIGHLIGHTS OF 2016

CORN ROOTWORM - Beetle counts decreased in 2016, though not uniformly. Populations were considerably lower than 2015 levels across southern, central and east-central Wisconsin, while counts in the three northern districts and west-central area exceeded both last year's populations and the 10-year average. The annual survey found a state average of 0.5 beetles per plant, a decline from 0.6 per plant in 2015. Results of the survey indicate generally lower rootworm pressure for southern and central Wisconsin in 2017. Larval root damage could be elevated across the northern areas next season.

BROWN MARMORATED STINK BUG - Populations are now firmly established in Dane and Rock counties. A collaborative monitoring survey by DATCP, UW and the IPM Institute resulted in the capture of 185 adult and nymph specimens in seven pyramid traps in south-central Wisconsin. The highest cumulative individual trap count of 80 stink bugs was documented in an orchard near Verona in Dane County. BMSB was found for the first time on apples in the state this season and its status could soon intensify from an urban nuisance to agricultural pest.

CORN TAR SPOT - Corn leaf samples from Green and Iowa counties tested positive for the tar spot fungus in 2016. The Green County sample was collected on September 12 and diagnosed by the Plant Industry Lab, with confirmation by an authorized USDA mycologist. A second Iowa County sample was confirmed by the UW Plant Disease Diagnostic Clinic on September 20. Tar spot of corn was first reported in the United States in 2015 in Indiana, and found later that season in Illinois. In 2016, the disease was again found in Indiana and Illinois, as well as in Iowa, Florida, Michigan and Wisconsin. Prior to the Indiana finding, tar spot was known to occur only in Latin America.

LILY LEAF BEETLE - This newly-established invasive pest was found in early August by a resident of Plover in Portage County, marking the southernmost detection of lily leaf beetle in the state. The northernmost record of the beetle is from Merrill in Lincoln County. Lily leaf beetle was first discovered in Wisconsin in 2014 and reproducing populations of this striking red insect currently exist in Lincoln, Marathon and Portage counties.

WESTERN BEAN CUTWORM - Moth numbers returned to moderate levels after a three-year low. The 2016 survey average count of 20 moths per trap was a noteworthy increase from seven per trap in 2015 and comparable to the 12-year average of 23 moths per trap. Larval infestations resulting from the flight were also more common this season, with larvae found in about 9% of the 458 cornfields sampled in August and September.

JAPANESE BEETLE - Populations were the highest in several years. Above-average rainfall, which favors the larval stages, and lack of natural controls appear to have been contributing factors to the abundance of beetles in 2016.

TWO-BANDED JAPANESE WEEVIL - A new state record was established in Dane County on August 5 following a Madison resident's report of numerous specimens on various ornamental plants. This detection marked the first confirmed account of the invasive Asian beetle in Wisconsin. The weevils were observed on columbine, coral bells, Japanese anemone, ligularia, pulmonaria, Siberian bugloss, snow-on-the-mountain, spirea, rock iris and assorted weeds. There has been no indication that infestations have spread beyond the Madison area.

-- Krista Hamilton, DATCP Entomologist