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 The following insecticides are suggested for alfalfa weevil control: 



1. Methoxychlor, 1 pound, plus diazinon, 1/2 pound (Alfatox) per acre. It is 

 effective for approximately 10 to 14 days. Do not harvest for 7 days after 

 treatment . 



2. Malathion, 1 pound per acre. It is effective for approximately 3 to 7 days. 

 Do not apply if air temperatures are below 60° F., since failure may result. 

 There is no waiting period between treatment and harvest. 



3. Methoxychlor, 1 pound per acre. It is effective for approximately 5 to 8 days. 

 Do not harvest for 7 days after treatment. 



4. Methyl parathion, 1/2 pound per acre. For use only by experienced applicators. 

 It is effective for approximately 8 to 12 days. Do not harvest for 15 days 

 after treatment. 



5. Azinphosmethyl (Guthion) , 1/2 pound per acre. For use only by experienced 

 applicators. It is effective for approximately 10 to 14 days. Do not apply 

 more than once per cutting. Allow 16 days between treatment and harvest. 

 Water temperature for the spray mix should be above 55° F. 



Rain immediately following spraying will generally reduce effectiveness, and a 

 repeat treatment may be needed. For pastures, use malathion since you can return 

 animals immediately after spraying. 



Clover leaf weevils, which can be easily confused with alfalfa weevils, are also 

 abundant in many clover and alfalfa fields. A few severely damaged fields have 

 been observed in the southern half of the state. 



This large, pale-green worm with white stripes down its back has a tan or brown 

 head- -rather than a black head like the alfalfa weevil. They hide down around 

 the base of the plants during the day, feeding mainly at night. A fungus disease 

 which causes the worms to turn cream and later black when dead (usually adhere 

 to leaves) is prevalent and killing larvae in many fields. Also many larvae in 

 the southern third of the state are through feeding, and pupation has started. 

 The current rapid growth of alfalfa and red clover should enable most stands to 

 outgrow damage. However, if weevil feeding begins to get ahead of plant growth, 

 a spray of one pound per acre of malathion is effective. Pea aphids are also con- 

 trolled by malathion. 



Pea aphids are common in many alfalfa and clover fields, but are not numerous 

 enough to be of concern. Parasitized (brown ones adhering to leaves) and diseased 

 pea aphids and aphid predators have already been observed, and these natural agents 

 may be sufficient to control problems . 



English grain aphid populations are heavy in occasional wheat fields, but no injury 

 is apparent from their feeding. There are many aphid predators present which will 

 help reduce aphid numbers- -particularly syrphid fly maggots. Aphids are of great- 

 est concern when populations are high at the time wheat is heading out. No con- 

 trol is needed unless the plants show wilting. 



