L. WENNEMANN, H.E. HUMMEL

MCA is an organic substance which is investigated for its potential as an orientation disruption tool with a possible effect as a mating disruptant for the western corn rootworm Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). For the formulation: A cement mixer was used to blend MCA dissolved in Acetone and corn grits (‘grits’). Grits are a  by-product after corn is harvested and separated from the cob.

This year’s studies included the improvement of the formulation technology by investigating  a) 4 corn grit sizes b) 3 loads of the mixer and c) variation in the amounts of liquid mixing media in conjunction with a food color. Distribution patterns by collecting grits in plastic dishes and counting grits on corn plants were investigated in the field after aerial and high wheel tractor application. Impact of MCA on beetle orientation in experimental fields sites in Kardoskut (Hungary) and Kula (Serbia) were evaluated by comparing number of beetles collected in Yellow Sticky traps, VAR trap, PAL traps and plastic cups coated with tanglefoot in the MCA treated and the control plots and by putting each a female into a 3-cm plastic can on top of a sticky trap sealed by a gaze. Females were collected in the treated and control plots after different time intervals. The spermatheca was checked for the absence and the presence of sperm to identify mating status.

Results of the formulation experiments showed that the optimal mixer load is 20 kg grits and MCA dissolved in 1 L of acetone. Both application techniques are valuable for grit distribution in the field. Preliminary analysis of the data showed variable orientation disruption of adult western corn rootworms. The tanglefoot coated plastic cups proofed to be a cheap and an excellent trapping device for adult rootworm. Single female traps revealed variable catching results in both the treated and untreated field. The dissection of the spermatheca did not show an effect of the MCA application on the mating status.