By Scout Nelson
Janet Knodel, an Extension entomologist at North Dakota State University, brings good news for North Dakota wheat farmers as recent soil samples show low populations of overwintering wheat midge larvae. This finding suggests a positive outlook for the 2024 wheat growing season, with reduced need for wheat midge management efforts.
In a comprehensive fall 2023 survey, 2,060 soil cores were collected across 22 counties to assess the risk of wheat midge for the upcoming season. The survey found wheat midge present in only 20 field sites across eight counties, all showing low levels of wheat midge cocoons that are not expected to impact spring wheat yields.
Knodel attributes the sustained low populations to the prolonged drought affecting northern North Dakota, which has disrupted the wheat midge lifecycle. Drought conditions cause larvae to remain in wheat heads, reducing their chances of successfully overwintering in the soil. Dry soil conditions lead to higher mortality rates by exposing larvae to predators and environmental stressors.
Despite the low wheat midge populations for four consecutive years, Knodel advises farmers to remain careful, especially in continuous wheat fields or during moist weather conditions that favor wheat midge emergence. She recommends using the wheat midge degree-day model for timely scouting and management decisions.
The economic thresholds for action against wheat midge are detailed, specifying the number of midges per wheat head that warrants management intervention to prevent economic losses.
The survey noted a decline in parasitic wasp populations, which are natural predators of wheat midge. This decline is directly tied to the low availability of wheat midge hosts, highlighting the interconnectedness of agricultural ecosystems.
The soil survey, facilitated by NDSU Extension County agents and analyzed by the NDSU Extension Entomology laboratory, is supported by the North Dakota Wheat Commission, underscoring the collaborative effort to monitor and manage crop threats effectively.
Photo Credit -gettyimages-ygrek
Categories: North Dakota, Crops, Wheat