 |
ProCrop |
Sunflower Beetle
The sunflower beetle has just one generation per year. Shortly after emergence the beetles begin to feed. There is seldom much damage to cotyledons, but the first true leaves can be severely damaged or completely consumed.
After mating, the female sunflower beetle deposits yellowish-green, oval eggs on stems and undersides of leaves. The number of eggs produced by a single female has been estimated to be at least 200. Eggs hatch into larvae in about one week. The larvae are present in fields for about six weeks. Egg laying occurs from late May through June.
Field monitoring for sunflower beetles should be at two locations (minimum) on each side of a field with one or two sampling sites near the center. Twenty plants should be examined at each sampling site for a total of 100 plants. To determine percent defoliation, examine a total of 100 plants divided among the sampling sites.
The economic threshold for adult sunflower beetles is 1 to 2 adults per seedling or about 10 larvae per seedling up to the 8 to 12 leaf stage.
Control (based on defoliation) is suggested when defoliation reaches the 25% to 30% level and it appears (based on larval size) that more defoliation will occur. If the majority of the larvae have reached maturity (about 1/4 inch size) at approximately 25% defoliation, control should not be necessary.
Insecticides registered for sunflower beetle control include:
Asana XL at 0.0075-0.03 lb AI/A (1.45-5.8 fl oz product per acre)
Baythroid at 0.125-0.025 lb AI/A (0.8-1.6 fl oz product per acre)
carbaryl (Sevin S or XLR) at 1.5 to 2 lbs. AI/A (rate varies by formulation product per acre)
Decis 1.5 EC at 0.012-0.018 AI/A (1.0-1.5 fl oz product per acre)
Furadan 4F at 0.125-0.5 lb AI/A (0.25-1 pt product per acre)
Lorsban 4E Warhawk/Yuma 4E at 0.5-0.75 lb AI/A (1-1.5 pts product per acre)
Proaxis 0.0075-0.0125 AI/A (1.92-3.2 fl oz product per acre)
Warrior/Taiga Z 0.015 - 0.025 lb AI/A (1.92-3.20 fl oz product per acre)
For more information consult the Insect Control Guide at http://www.ext.nodak.edu/extpubs/plantsci/pests/e1143w1.htm
Back to Insect - Sunflower
Menu
Back to Sunflower Beetle - Sunflower Menu
Back to Sunflower Menu
Back to Main ProCrop Index
