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1. E-912 - Chapter 13 - Red And Gray Sunflower Weevil
(Slide courtesy of D. K McBride, and top caption courtesy North Dakota Coop. Ext. Service.) Figure 25. Red and gray sunflower weevil.
Red and Gray Sunflower Weevil
Category: NOLI
Minimum Life Cycle: One year.
Distribution: Areas with sunflower farming, especially the Dakotas. Not injurious to stored grain. Two species: red and gray sunflower weevil.
Eggs -
Deposited in immature sunflower seeds in late summer.
Larvae - Develop inside sunflower seeds. Infested seeds are often harvested. Larvae drop from the infested heads and pupate in the soil.
Adults - Emerge the next summer and feed on foliage and pollen. Do not reinfest stored products. Red and Gray Sunflower Weevil (Smicronyx fulus and S. Sordiadus). The red sunflower seed weevil adults are reddish brown, and the gray sunflower seed weevil are slightly larger and gray in color. The larvae of both species are small, cream colored, legless, and C-shaped in appearance. Seed weevil adults emerge in mid summer and feed on sunflower buds. As the sunflower matures, the adults feed on pollen, and, as the seeds mature, eggs are deposited within the seed. After developing in the seed, the larvae drop to the ground, overwintering in the soil. The insect is univoltine in North Dakota, cannot survive in storage, and is not a stored product pest (Figure 25). (Slide courtesy of D. K McBride, and top caption courtesy North Dakota Coop. Ext. Service.)

2. Noxious Weed IVM Guide- Leafy Spurge
North Dakota Coop. Ext. Service, pp. 5369. Bandsund, D.A. and F.L. Leistritz. 1991. Economic impact of leafy spurge in Montana, South Dakota, and Wyoming.
Noxious Weed IVM Guide Contents IVM for Noxious Weeds Broom Canada Thistle ... Home Page IVM Technical Bulletin
Leafy Spurge
Gather Background Information The first step in an IVM program is to gather information on the life cycle and habits of the noxious weed. Description
Leafy spurge is a deep-rooted perennial weed of the family Euphorbiaceae. Because certain structural characters of the weed are very variable, there has been some confusion about how to classify it taxonomically. In North America it is commonly referred to as Euphorbia esula (Watson 1985). Leafy spurge grows as clusters of upright stems one to three feet tall. The stems are erect, tough and woody, and frequently have many non-flowering branches. The plant emerges in early spring, producing bright yellow bracts which appear from early to late May, with the true flower emerging in mid-June. The bracts surround a cluster of 11-20 small, stalked yellow-green flowers. Leaves are dark blue-green, hairless, narrow, and alternate on the stem. Maturing stems change color from pale green in early summer to yellow or red in the fall. Leafy spurge can be distinguished from other plants by the white sap that will ooze from all parts of the plant when cut or broken open (Lajeunesse et al. 1995; Lym 1991). Damage
Leafy spurge is an aggressive weed that tends to displace all other vegetation in pastures and rangelands. The latex in leafy spurge is a skin irritant that can cause severe dermatitis in humans and grazing animals, and is unpalatable and toxic to cattle and horses. Cattle and horses generally avoid leafy spurge, but if ingested it causes scours and weakness that may result in the death of the animals. Sheep and goats are not affected by the toxin and can eat young leafy spurge plants (Muller et al. 1990).

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