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What's bugging you?By Assefa Gebre-Amlak Crops and Protection Agent Sunflower moth It is time for scouting for the Sunflower Moth and the Banded Sunflower Moth in northeastern Colorado. Historic data from Colorado State University show moth flight for both species start around mid July. Reports from the Kansas State University showed that head moth numbers in traps have been increasing. The Sunflower Moths migrate from southern states and are attracted to sunflowers beginning to bloom. Immature larvae feed on florets and pollen. As they mature, the larvae tunnel into seeds and other parts of the sunflower head. As the larvae feed and spin silken threads, the dying florets and frass give the sunflower head a trashy appearance. The larval feeding also provides entrance for fungi that causes Rhizopus Head Rot. Banded Sunflower Moths emerge from previous sunflower fields locally in Colorado. Scouting for both species of moths should be done in the early morning or late evening, at dark, using a flashlight. Two Sunflower Head Moths per five plants would justify treatment. Currently, there is not a set economic threshold for the Banded Sunflower Head Moth. However, two moths per five heads during the late bud stage or very early bloom stage (ray petals formed and just opening) can be used as a guideline for treatment. Treatment for both species of sunflower moths should be made at early bloom to prevent moths from laying eggs. Early planted flowers are blooming in the area and these fields should be scouted now. Generally early planted sunflower fields have higher head moth infestations than the late planted flowers. If you are using a pheromone trap to monitor the head moth, research data indicate that treatment should be considered if trap catch averages four or more head moths per night. However, the use of pheromone traps for Banded Sunflower Head Moth has not shown a relationship in the number of insects caught per night and economic damage. Normal scouting, along with pheromone traps, should be conducted to determine the presence and infestation levels of these insects. The product list for Banded Sunflower Moth and Sunflower Moth include Asana XL, Baythroid XL, carbaryl, chrlopyrifos, lamda cyclohathrin, and Proaxis. Western bean cutworm The Western Bean moth flight peaked between July 11 and 17 in Kirk area, southern Yuma County. Last week we saw a clear decline in moth populations in our trap. Field scouting in the Golden Plains area showed more than 90% egg hatch. When scouting for western bean cutworms in cornfields, check 20 plants in at least five locations of each field. Look for eggs on the top surface of the upper leaves or look for larvae in the tassel. Chemical control should prove economical if eight percent or more of the plants have egg masses or small larvae in the tassels, and the crop is at least 95 percent tasseled. If tasseling is much less than this, the percentage of infested plants should be raised as fewer larvae are likely to reach the ears. Effective products for western bean cutworm control include Asana, Baythroid, bifenthrin, chlorpyrifos, lambda cyhalothrin, Mustang Max, Penncap-M, Mustang Max, Permethrin, and Tracer. Western corn rootworm beetles Corn rootworm beetles started to emerge in most of the Golden Plains Area but numbers are still too small to warrant any control measure. If your field has a history of a corn rootworm problem, it should be scouted for rootworm. Control of rootworm adults is intended either to protect silks during pollination or to prevent egg laying and damage to roots in next year's crop. Control may be justified if there are more than 10 beetles per ear zone during the wet silk stage. If treatment is intended to prevent egg laying, then treatment is recommended when beetle counts exceed 18,000 beetles per acre (three beetles in four plants at 24,000 plant populations per acre). Adult treatment applied too early, that is, before 10 percent of females are carrying fertile eggs (female beetles with swollen abdomens), may not have much effect on egg laying. Generally the proper time for application for adult treatments occurs two to three weeks after the first adult emerges. A second adult treatment should be considered if beetle densities rebound to 12,000 per acre (one beetle in two plants at 24,000 plants per acre). If field scouting shows presence of both Western Bean Cutworm and Western Corn Rootworm beetles at economic levels, a singular application may be used to control them. The products listed for control of western bean cutworm including Ambush 2ER,1, Furadan 4F, malathion, methyl parathion, Penncap-M may be used at label rates to control adult corn rootworms. (RRestricted use pesticide and 1Labeled for chemigation). For more detailed information on effective products including rates of application for insects mentioned in this article, check the regional IPM guide at www.highplainsipm.org. Date: 7/25/06
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