Crop & Pest Report


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Watch Out for these Invasive Insect Pests (05/21/15)

Since the cold temperatures have slowed insect pest activity this past week, I thought this would be a good opportunity to update you on the status of a few invasive insect pests of field crops. Please look for these invasive insect pests when you are out scouting fields or around your home.

Watch Out for these Invasive Insect Pests

Since the cold temperatures have slowed insect pest activity this past week, I thought this would be a good opportunity to update you on the status of a few invasive insect pests of field crops. Please look for these invasive insect pests when you are out scouting fields or around your home. Send any suspect specimens to me for confirmation. Thank you for your help in finding these invasive insect pests.

 Brown Marmorated Stinkent.jk.1.bmsb Bug (BMSB) – The BMSB is getting closer to North Dakota. It has been detected in 42 states since its introduction in 2001 into the United States. The closest neighboring states with BMSB are Minnesota, Iowa and Nebraska. It has a wide host range infesting fruits, vegetables, and field crops (soybean, dry bean, field corn). If it is not being a problem damaging crops, this stink bugs invade houses in the fall, similar to boxelder bugs! You can identify it by its large size (3/4 inch), mottled brown appearance, and alternating light and dark band on the antenna and abdominal edges. Feeding injury symptoms appear as necrotic spots that look like a lesion on leaves, fruits, or pods. It is becoming a major pest of corn and soybean in the eastern United States.

 Sipha maydis – A new ent.jk.2.sipha mayisspecies of aphid, Sipha maydis, was discovered feeding on grain crops in western Colorado in 2015. Sipha maydis is native to Europe, Asia, the Middle East and northern Africa and was introduced into the United States in 2007. It was first found in California in 2007, Georgia in 2012, New Mexico in 2014 and Colorado in 2015. Sipha maydis can be identified as a black aphid with numerous white hairs covering the abdomen and short cornicles. The ESA accepted common name will be the “hedgehog grain aphid.” It feeds on a wide range of grasses including oats, wheat and barley. Symptoms of feeding injury includes chlorosis of leaves at feeding sites of colonies. The scientific literature on S. maydis is limited; however, it indicates that it is a vector of barley yellow dwarf virus and cucumber mosaic virus.

Japanese Beetle - The Japanese ent.jk.3.jap.beetle.adultbeetle, Popillia japonica, belongs to the insect family Scarabaeidae. The adult Japanese beetle is oval-shaped and approximately ½ inch long and ¼ inch wide. The head and thorax are metallic green, and the wing covers are typically coppery-purple bordered with green. You can identify it from other beetles by the five patches of white hairs protrude from each side of the abdomen. It is a highly destructive plant pest that feeds on more than 300 host plants, including field crops (especially corn and soybeans), ornamental trees and shrubs, garden flowers and vegetables, and turf (lawns, pastures and golf courses). Adult beetles defoliate the leaves and some of the preferred host plants are rose, apple, black cherry, cherry, flowering crabapple, plum, grapes, hollyhock, blackberry, raspberry, linden, elm and buckeye. Grubs are found primarily in the root zones of grasses where they feed on the roots. Grubs are about 1 inch long when mature, C-shaped and creamy white with a brown head capsule. White grubs are identified using the pattern of hairs (rasters) that form a V just below the anal slit on the end of the abdomen.

Japanese beetle is found in our neighboring states:  Minnesota, South Dakota and Montana. It first was detected in North Dakota in 2001 in Bismarck, but it did not become established. In 2012-2014, the Japanese beetle was detected at several locations in North Dakota, including Bismarck, Fargo, Grand Forks, Minot, Oakes, Taylor, West Fargo and rural Foster County. Upon investigation, the source of the infestation was identified as infested nursery stock that was shipped into North Dakota. At this time, whether any Japanese beetle will become established in North Dakota is unknown. To determine if it is present in North Dakota, the North Dakota Department of Agriculture (NDDA) has organized a pheromone trap survey using a total of 1900 traps or about 25 traps per county of North Dakota. If you are interested in volunteering for the NDDA Japanese beetle survey, please go to the North Dakota Department of Agriculture website to sign up.

Once established, it can be a difficult and expensive insect pest to control. Control costs for Japanese beetle are estimated at approximately $450 million each year in the United States. Please see the NDSU Extension Service factsheet E1631 Integrated Pest Management of Japanese Beetle in North Dakota for more information.

Swede Midge – The swede midge, Contarinia nasturtii, adultwas introduced in the United States in 2004 in New York, and has spread westward in Canada (Manitoba, Saskatchewan, and Nova Scotia). This tiny mosquito-like midge infest plants in the family Brassicaceae, such as canola, mustard, cabbage, cauliflower and several Brassica weeds (wild mustard). The adult is a small, brown fly about 1.5-2 mm and is difficult to distinguish from other midges except by a trained entomologist. Damage symptoms appear as abnormal growth, puckered leaves, distorted growing points, or leaves and flowers with gall formations. Symptoms are difficult to distinguish from herbicide injury, heat or cold stress; however, tiny white larvae (3-4 mm when mature) should be found inside the plant tissues. Due to the recent detection of swede midge in a pheromone trap in canola near Winkler (Manitoba) in 2014, NDSU Extension Service will be running 13 trap sites in Pembina, Cavalier and Towner Counties in northeast North Dakota. Any positive results will be posted in future issues of the Crop & Pest Report. Thank you to the Northern Canola Growers Association for support of the swede midge trapping network.ent.jk.4.sml












Janet J. Knodel

Extension Entomologist

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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