68 



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



phlox stems behind the leaf petioles, and 

 the winter is passed in the egg stage. 

 In the vicinity of Washington, D. C., 

 overwintering eggs begin to hatch early 

 in May, and the nymphs develop to 

 adults in a few weeks. Two or more 

 generations develop, and by midsummer 

 all stages of the insect are present. 



Treatment. — As soon as growth 

 starts in the spring, watch for the first 

 evidence of their appearance and feed- 

 ing. Dust the plants with dusting 

 sulfur, or preferably a mixture consisting 

 of 3 parts of dusting sulfur and 1 part of 

 pyrethrum dust (containing 0.9 to 1.3 

 percent of total pyrethrins) by weight. 

 Apply several times at intervals of a 

 week or 10 days until the insects have 

 been controlled. Spraying with a 

 strong pyrethrum spray is also useful. 



Prevention. — Cut and burn the old 

 stalks, preferably after the first killing 

 frost or late in the fall; cut as close to 

 the ground as possible. Avoid splitting 

 the stems, otherwise the eggs are likely 

 to fall to the ground or into crevices 

 where they might get the needed pro- 

 tection against winterkilling. Raking 

 up and burning all debris and weeds in 

 the infested area is also of value. If the 

 old stems are left on the plants, the 

 nymphs will hatch in the spring and 

 attack the new growth during the sub- 

 sequent growing season. 



Other Pests of Phlox 



Page 



Four-lined plant bug 94 



Red spiders 11 



Blister beetles 7 



Asiatic garden beetle 21 



Stalk borer 34 



Corn earworm 29 



Golden tortoise beetle 59 



White grubs 14 



Wireworms 15 



PINE 

 Pine Sawflies 



The larvae of several sawflies, es- 

 pecially those belonging to the genus 

 Neodiprion, feed on the needles of pine. 

 They resemble hairless caterpillars and 

 for this reason are sometimes called false 

 caterpillars. When full-grown these 

 larvae are nearly an inch long. The 

 different species may be pale yellowish 

 or greenish, with broad dull stripes or 

 black spots along the body. They feed 

 in groups (fig. 113), devouring the 

 needles and leaving only the basal por- 

 tions or bundle sheaths. Their growth is 

 completed in from 4 to 6 weeks, and 

 then they enter the litter or soil to spin 

 cocoons. The wasplike adults emerge 



Figure 113. — Introduced pine sawfly 

 larvae (Diprion simile (Htg.)) feeding 

 on pine needles. Natural size. (Brit- 

 ion.) 



later and deposit eggs in slits ''sawed" 

 in the pine needles. 



The red-headed pine sawfly (Neodi- 

 prion lecontei (Fitch)) produces two 

 broods of larvae in the North, occurring 

 in late spring and late summer, and at 

 least three broods during a season in the 

 South. The early broods eat mostly the 

 old needles. The late broods eat both old 

 and new foliage and consequently may 

 entirely strip small trees and thus cause 

 their death. Injury is sometimes in- 

 creased by their feeding on the tender 

 bark of twigs. Other sawflies have 

 only one generation a year, the larvae 

 being present for a period of about 6 

 weeks in the spring and feeding on the 

 old needles. A small percentage of the 

 larvae may remain in the soil for 2 years, 

 the adults then emerging to continue 

 the infestation; consequently it is ad- 

 visable to watch for additional infesta- 

 tion the second season, even though 

 control measures have been applied. 



