HANDBOOK OX INSECT ENEMIES OF FLOWERS AND SHRUBS 15 



Figure 24. — A white grub, the larva of 

 a May beetle. Twice natural size. 



Treatment. — White grubs are often 

 a pest in ground which has been in sod 

 for several years and which is being 

 planted for the first time. Generally 

 the practice of turning the soil in late 

 summer or early fall or carefully work- 

 ing it during the spring, and killing such 

 grubs as are found, is helpful in ridding 

 the flower garden of grubs. 



When the infestation is heavy enough 

 to warrant treatment, undiluted car- 

 bon disulfide may be used as recom- 

 mended on page 103. Another method, 

 especially useful on small areas of lawn 

 or garden, consists of treating them with 

 a carbon disulfide emulsion prepared 

 and applied according to the directions 

 given on page 104. 



Grubs in the lawn may also be killed 

 by applying lead arsenate to the turf at 

 the rate of 1 pound to 100 square feet 

 of area. To obtain a more uniform 

 distribution, it should be mixed with 

 sand or dry soil at the rate of 1 pound of 

 lead arsenate to 1 peck of sand or dry 

 soil and then broadcast over the sur- 

 face. Lead arsenate, however, is likely 

 to injure young plants for several sea- 

 sons following application : consequently, 

 it is not advisable to apply it to soil in 

 the flower garden. 



WIREWORMS 



Wireworms, as their name implies, 

 are slender larvae (fig. 25) with cylin- 

 drical, wiry, smooth, shiny bodies. 

 They grow to about an inch in length, 

 usually requiring more than one season 

 to develop, and are pale yellow to 

 brown. Wireworms feed on the roots 

 of pansies and asters and burrow into 

 corms, bulbs, tubers, and the fleshy 



underground parts of plants. They are 

 often found partially buried in these 



feeding burrow.-. The adults are 

 slender, brown to black beetles about 

 l 2 inch long, and are known as click 

 beetles. 



Treatment. — Fertilizing to increase 

 plant vigor will lessen the seriousness of 

 injury due to wireworms. Deep plow- 

 ing in midsummer is helpful. In small 

 plantings the wireworms may be col- 

 lected during spading operations and 

 killed. In case of a heavy, persistent 

 infestation a new piece of ground 

 should be selected for planting. When- 

 ever possible avoid planting susceptible 

 crops in sod lands or other soils infested 

 with wireworms. 



The soil may be fumigated with car- 

 bon disulfide as described under "Fumi- 

 gants" or with crude naphthalene. If 

 naphthalene is used it should almost 

 come in contact with the wireworms to 

 be effective. The naphthalene should 

 be thoroughly mixed with the soil to a 

 depth of 7 to 12 inches late in the 

 spring or early in the summer, when the 

 wireworms are nearest the soil surface. 

 Best results have been obtained by 

 spreading 2 ounces to every 10 square 

 feet of soil surface, 1 ounce before disk- 

 ing and plowing and the second ounce 

 after plowing but before a second disk- 

 ing. In small areas the first ounce may 

 be chopped into the soil with a hoe before 

 spading. The second ounce may then 

 be applied after spading and raked into 

 the soil. 



Figure 25.- — Wireworms. About twice 

 natural size. 



