64 MISC. PUBLICATION 626, U. S. DEPT.'OF AGRICULTURE 



Figure 104. — The imported cabbage 

 worm feeding on nasturtium leaf. 

 About natural size. 



side of the body. The winter is passed 

 as a naked chrysalis, or pupa, which 

 may be found attached to various ob- 

 jects, including the boards of buildings. 

 Treatment and prevention. — Same 

 as for the cabbage looper (p. 3). 



Other Pests of Nasturtium 



Page 



Greenhouse leaf tier 5 



Corn earworm 29 



Tarnished plant bug 35 



PALMS 



Palm Leaf Skeletonizer 



The palm leaf skeletonizer (Homa- 

 ledra sabalella (Chambers)), also called 

 the palm leaf miner, attacks many 

 varieties of palms and decreases their 

 value for decorative purposes. The 

 caterpillars feed under a webbing on the 

 upper and lower leaf surfaces and make 

 dark-brown splotches (fig. 105), which 

 eventually cause the leaf to dry up and 

 die. This insect is especially injurious 

 in Florida, although it is likely to occur 

 in other southern States where palms 

 are used for decorative plantings in 

 gardens. Sabal palmetto and Canary 

 Island date palm seem to suffer most. 

 The tiny adult moths are rarely seen, 

 as they are active at night. The female 

 lays her eggs on the interleaf husks. 

 There are possibly five broods of cater- 

 pillars annually, and the winter is 

 passed in the egg, larval, and pupal 

 stages. 



Figure 105. — Feeding injury by the 

 palm leaf skeletonizer on portion of 

 palm leaf. 



Treatment. — Cut out and burn in- 

 fested fronds, otherwise the insects 

 therein will complete their development 

 and cause reinfestations. Spray with 

 lead arsenate, with a sticker added to 

 make the spray adhere better to the 

 waxy foliage. To avoid the white spray 

 deposit, a green-colored lead arsenate 

 can be used. Pyrethrum sprays kill 

 such larvae as are reached by this 

 insecticide. 



Prevention. — Remove and burn all 

 interleaf husks on plants, as the eggs 

 are laid on such tissue. 



Ground Mealybug 



In California the ground mealybug 

 (Rhizoecus terrestris (Newst.)) is de- 

 structive to palms, especially those of 

 the Kentia type. It has also been 

 recorded on acacia, boxwood, chrys- 

 anthemum, Shasta daisy, larkspur, 

 marguerite, petunia, privet, fruit trees, 

 and many weeds and grasses. This 

 mealybug occurs on the roots and injures 

 the plants by sucking the juices. It is 

 very small, pale, and thinly covered 

 with a white powdery wax (fig. 106). 



Figure 106. — Ground mealybug adult. 

 About 7 times natural size. 



