Show ir EARLY ARLY HAY CUTTING CONTROLS WEEVIL IN ALFALFA FIELDS by W W owens U S A C extension service editors note this la Is the fourth of a series of 0 seven articles prepared by sir air owens tor for this paper on weevil control the cheapest and most effective method to control the alfalfa weevil Is to cut the first crop of 0 alfalfa when it Is in one tenth bentli bloom and cut the second crop 35 to 40 days after the first cutting this controls the weevil tor for the following year this practice reduces to a minimum the number of adult weevils that live over tile the following year it is these over wintering weevils that lay the eggs which hatch into the hungry groen green worms that do the damage the early hatched worms all tall fall victims to the weevil parasite which lays its eggs in the worms later in the season the parasite misses a tew few worms and unless something else happens to destroy them they go through the cocoon stage and emerge as beetles which live until the next year cutting and harvesting the hay bay checks the growth of 0 the weevils in tile the worm stage so that but very tory few of them spin cocoons worms that started in the cocoon stage just before the hay was cut are killed hilled by the heat of the sun when their shade Is taken away it if the hay bay Is cut early all except two or three per cent of the worms that have started spinning cocoons will die because they contain parasite eggs tile the small percentage escaping the parasite will have only started their cocoons the last week before the hay Is cut and the sun will kill the worms now consider what happens ihn cutting of 0 the first crop Is delayed one or two weeks the parasite Is less effective eight or ten per cent of the worms escape it and these are given enough time to develop into beetles and crawl away so the heat of 0 the sun has no effect on them when the hay lay Is cut As a result a heavy crop of weevils la Is assured the following year the same principles apply to the second crop although there la Is no damage in tact fact worms are hardly to be found this crop must be cut early or enough weevils will mature to overbalance over balance the good effects of cutting the first crop early the program of weevil control places no restriction upon the handling of the third crop another advantage of early cutting is improved quality of hay it may mean less pounds of 0 hay per acre from the first two crops but in feeding value it means more pounds of butterfat butter tat beet beef or lamb per acre this early cutting must be practiced every year whether the hay shows weevil damage or not it takes only two female weevils per square toot foot to lay eggs to produce enough worms to riddle that square toot foot of hay there ars usually enough weevils in utah fields to propagate a damaging number for or the following year it they are given a chance |