HANDBOOK OX INSECT ENEMIES OF FLOWERS AXD SHRUBS 



by placing collars made of stiff card- 

 board, tar paper, or tin about them, 

 inserting the base of the collar an inch 

 or more into the soil, 2 inches sbove, and 

 about Yi inch from the plant stem. 



ARMYWORMS 



Armyworms are closely related to 

 cutworms. These caterpillars derive 

 their name from their habit of traveling 

 in hordes, or "armies," in search of food. 

 Infestations usually originate in the 

 spring in fields of small grains, and when 

 this food supply gives out the cater- 

 pillars move to adjacent areas. Gar- 

 dens in their path are invaded, and 

 all kinds of plants may be quickly 

 stripped of their foliage and destroyed. 

 The common army worm (Cirphis uni- 

 puncta (Haw.)) is a widely distributed 

 species, and at times other species may 

 be encountered. The caterpillar (fig. 3) 

 is dark green, marked with white stripes, 

 and about Vfa inches long. It hides 

 under clods or litter during the day and 

 feeds at night. The adult is a pale- 

 brownish moth. This worm passes the 

 winter as a partly grown larva. 



Figure 3. — Full-grown caterpillar, or 

 larva, of the armyworm. About 

 natural size. 



Treatment. — Use the poisoned-bran 

 mash recommended for cutworms (p. 

 2), or spray or dust the plants with 

 lead arsenate. 



Prevention. — For larger gardens or 

 nurseries, the advancing worms may be 

 stopped by digging a ditch with vertical 

 sides for the worms to tumble into, 

 where they can then be killed by 

 dragging a log back and forth or by 

 spraying them with kerosene. 



CABBAGE LOOPER 



The cabbage looper (Trichoplusia ni 

 (Ffbn.)) is an example of a caterpillar 

 that feeds more or less exposed on the 

 plant, in contrast to cutworms and 

 borers, which are usually not seen. 

 Although this species is chiefly a pest 

 of cabbage, it is often found chewing 

 irregular holes in the leaves and buds 

 of carnation, chrysanthemum, mignon- 



ette, geranium, German ivy, and many 

 other flowering and ornamental plant-. 

 The cabbage looper derives its name 

 from its preferred economic food plant 

 and its curious looping or measuring 

 movement (fig. 4) while crawling. The 

 caterpillar is delicate pale green when 

 first hatched. When full-grown it is 

 about 1% inches in length and green 

 with a white stripe along each side of 

 its body. The adult is a medium-sized 

 grayish-brown moth. 



Figure 4. — Cabbage looper feeding on 

 a leaf. About natural size. 



Treatment. — The caterpillars can 

 be poisoned by spraying or dusting the 

 foliage with lead arsenate. Derris or 

 cube dusts (p. 100) containing from 0.5 

 to 1 percent of rotenone give satis- 

 factory control. Pure, fresh pyrethrum 

 dusts (p. 98) containing 0.15 percent 

 of total pyrethrins are also effective. 

 Use the commercially prepared dusts 

 of derris and pyrethrum according to 

 the directions furnished by the manu- 

 facturer, because the dusts may vary 

 in strength. Treatments with these 

 dusts should begin when the worms 

 first appear and be repeated as often 

 as necessary to protect the plants. To 

 reach the insects, dust thoroughly all 

 infested parts of the plant. 



Prevention. — Cleaning up and burn- 

 ing in the fall all crop remnants, and 

 such weeds as mustard, shepherds-purse, 

 and pepper grass that may be near the 

 garden will aid in keeping down the 

 number of worms. 



YELLOW WOOLLY BEAR 



The yellow woolly bear (Diacrisia 

 virginica (F.)) is a hairy caterpillar that 

 occurs throughout the United State>. 



