Forages & Grains
Volume 64 Number 13 Date 07/25/2019
POTATO LEAFHOPPER - Pressure in alfalfa, apple orchards, and other crops has been very high this season. The counts recorded by DATCP during its July surveys are the highest in several years. Of the 38 alfalfa fields sampled this week in Dodge, Green, Iowa, Jefferson, Juneau, Lafayette, Marathon, Marquette, Monroe, Portage, Richland, and Sauk counties, 23 or 61% had economic counts of 2.0-5.3 adults and nymphs per sweep, with the largest numbers observed in Sauk County.
JAPANESE BEETLE - Adults are prevalent in alfalfa sweep net collections, especially in southern and western alfalfa fields where counts occasionally average 0.5-0.9 per sweep (50-90 per 100 sweeps). The abundance of beetles signals that heavy egg laying is occurring.
PLANT BUG - Mixed populations of alfalfa and tarnished plant bugs currently average 0.3 per sweep, which is very low in comparison to the 5.0 plant bug per sweep threshold. The week's highest count of 1.4 per sweep was noted in Iowa County.
PEA APHID - Levels of this insect in alfalfa were extremely low at less than 1.5 aphids per sweep (150 aphids per 100 sweeps). The July 18-24 average of only 0.6 per sweep suggests that aphid pressure in generally very low at this time.
-- Krista Hamilton, DATCP Entomologist