204 MANUAL OF VEGETABLE-GARDEN INSECTS 



beetle is very troublesome in newly set beds. Frequent de- 

 foliation weakens the plants, making it difficult for them to 

 become established. 



The common asparagus beetle is held in check by a small 

 Chalcid parasite, Tetrastichus asparagi Crawford, the life his- 

 tory of which is remarkable. The adult parasite appears in 

 the asparagus field in the spring while the eggs of the beetle 

 are being laid. The female inserts her eggs in those of the 

 beetle. The beetle egg hatches and its larva, containing the 

 larvse of the parasite, reaches maturity, enters the ground and 

 constructs its pupal cell but does not pupate. The parasites 

 then complete the destruction of the host and emerge from its 

 shriveled remains, pupate within the cell constructed by the 

 beetle larva and later emerge as adults. From one to ten para- 

 sites have been reared from a single beetle larva. 



Methods of control. 



In asparagus fields in which the crop is being cut for market, 

 the injury to the young shoots by the larvae may be prevented 

 by cutting the crop clean every three to five days. In this way 

 all the eggs deposited on the shoots will be removed before or 

 very soon after hatching. All volunteer plants should be de- 

 stroyed but it will often pay to leave a row here and there 

 uncut to serve as a trap on which the beetles will congregate, 

 feed and lay their eggs. Here they may be poisoned with 

 arsenate of lead (paste), 1 pound in 20 gallons of water, or the 

 plants may be cut and burned, thus destroying the early stages 

 of the beetle. After the cutting season is over, the plants may 

 be protected from beetle injury by two or three applications 

 of arsenate of lead (paste), 1 pound in 20 gallons of water. It 

 is not an easy matter, however, to spray thoroughly a large 

 field of asparagus when the plants have made a heavy growth. 

 In newly set beds, spraying with arsenate of lead is often re- 

 sorted to with satisfactory results. In this case the application 



