Issue No. 4, Article 1/April 16, 2004
Alfalfa Weevil Update
We've had few reports concerning alfalfa weevils this week. One in particular, though, is newsworthy. Kevin Black, with Growmark, reports early tip feeding from alfalfa weevils is being seen in southern Illinois and should be observed in areas as far north as Highway 136. Remember, initial injury caused by the larvae appears as pinholes in the leaf terminals. As larvae continue to develop and increase in size, damage also increases. Severe damage can cause the leaf to appear to be skeletonized. For more information on alfalfa weevil feeding and injury, see the new fact sheet.
Degree-day accumulations in southern Illinois indicate first and second instars should be present in alfalfa fields and feeding in leaf terminals. Degree-days across much of Illinois will be nearing 300, signifying the beginning of leaf feeding in the next two weeks (Table 1). For degree-day accumulations and projections near you, visit our degree-day calculator.--Kelly Cook