Janet J. Knodel
Extension Entomologist
The goal of the IPM Survey is to detect the presence severity of diseases and insect pests that are common in agricultural crops grown in North Dakota and to verify the absence of pests that might be of export concern. The following crops were surveyed in 2014: wheat, barley, canola, soybean, and sunflower. Survey scouts operated out of the Dickinson Research Extension Center, the North Central Research Extension Center (Minot), the Williston Research Extension Center, the Carrington Research Extension Center, the Langdon Research Extension Center, and the Fargo Agricultural Experiment Station. NDSU IPM field scouts surveyed a total of 3491 wheat fields, 327 barley fields, 1261 soybean fields and 315 sunflower fields. In addition to fields surveyed, field scouts also set out pheromone traps for sunflower insects and two exotic insect pests, as well as collected soil samples from wheat fields for exotic nematode detection. University of Minnesota Extension cooperates with NDSU Extension on the IPM Survey for wheat and barley.
Some of the IPM highlights for insect pests are summarized below:
Grasshoppers were surveyed in field edges of all crops. A total of 4,915 fields was surveyed in North Dakota and Minnesota. Grasshoppers were found in 41% of fields surveyed from early June through the end of survey (mid-August). The average number of grasshoppers per square yard was only 2.6 with ranges from 1 to 125 per square yard. Populations of grasshoppers were the highest in the northwest, central and southeast regions of North Dakota. Most fields were generally below recommended treatment levels throughout North Dakota (see map). This may have been due to the wet weather conditions in June that were not favorable for grasshopper emergence and development.
WHEAT: Small Grain Aphids were found in about 18% of the fields surveyed (see map). The average was low with only 15.9% of the plants infested with aphids, with ranges from 0 to 76%. Aphids were detected late - end of June or early July. The cool wet June kept aphid populations low and few insecticide treatments were needed for control of wheat aphids. The treatment threshold is when 85% of stems have one or more aphids present prior to completion of heading.
Wheat stem maggots (Meromyza americana) were low and observed in only 10% of fields surveyed in 2014. The range was from 1 to 28 percent of infested plants with white heads.
Wheat stem sawfly (Cephus cinctus) populations continue to be low and observed in only 1% of the field surveyed in 2014. The number of sawflies per 20 sweeps ranged from 1 to 9.
Cereal Leaf Beetle: Cereal leaf beetle (Oulema melanopus) is an export concern for shipments of hay from North Dakota to California or Canada and is monitored for state regulatory purposes. Cereal leaf beetle was detected in 12 wheat fields in Williams and McKenzie Counties of North Dakota. However, these counties are already confirmed as positive for cereal leaf beetle.
BARLEY: The number of barley thrips (Limothrips denticornis) was detected in only 8% of the fields surveyed. However, the average number of thrips per stem was 8.4, with ranges between 2 and 28. Economic levels of barley thrips is at 4-8 thrips per stem based on 2014 market prices for barley. High populations were detected in the central region of ND.
SOYBEAN: Soybean Aphid (Aphis glycines) were found in 20% of all fields surveyed and were observed from late July to the end of survey period (mid-August), mainly in southeast North Dakota. Soybean aphid population increased rapidly after the IPM Survey was done. Many fields reached economic threshold levels late (mid- to late August) and required an insecticide treatment for control of soybean aphids.
Source : ndsu.edu