32 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



SUMMARY OF HABITS. 



From present kno^Yledo•e of the caterpillar two generations annually 

 are indicated, although onh^ one has been observed. Moths have been 

 reared by the writer in July and August and they have been captured 

 out of doors during the same months and in September. From 

 available data it would appear that an average life history would be 

 about as follows: Egg period, 3 to 5 days; first larval instar, 3 days; 

 second larval instar, 2 days; third, 5 days; fourth, 4 days; fifth, 

 8 days, and pupal stage, 7 to 10 months. Hibernation occurs in the 

 pupal stage. 



The observed food plants include asparagus, cabbage, collards, 

 turnip, ruta-baga, rape, peas and related j^lants, greenhouse violet, 

 tobacco, grass, and blackberry. Of wild plants, golden-rod and 

 milkweed haA'e been observed, the larva attacking the flowers of 

 the former and the seed ix)ds of the latter. 



METHODS OF CONTROL. 



Although the early habits of this species as it occurs in the field 

 have not been observed, there is no doubt that, like the zebra cater- 

 pillar, the young when first hatched are gregarious for some time, 

 and hence may be easily discovered and destroyed by mechanical 

 means or by arsenicals. All of the caterpillars of this class readily 

 succumb to arsenical poisons, and for this species in its occurrence on 

 asparagus and some other plants arsenate of lead is to be preferred. 

 It may be used at the rate of about 1 pound combined with 15 to 25 

 gallons of water or Bordeaux mixture. If an adhesive resin soap, 

 such as resin fish-oil soap, is added, it makes this mixture all the 

 more permanent, and a single application is then all that is necessary. 

 Paris green may be used in the same manner at the rate of 1 pound 

 to 100 or 150 gallons of water. It is evident that this species, like 

 the zebra caterpillar, does no particular harm as a rule in its first 

 generation, but is much more abundant in the second or late fall gen- 

 eration, when certain plants are injured by it. Owing to the diffi- 

 culty of locating tlie larger larvw, it is evident that hand-picking 

 would not be applicable for them in their later stages. 



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