560 EXPERIMENT STATION EECORD. 



Tlie next best conditions are where the branches may fall on hard j^cround 

 where they may be protected from moisture to some extent and conseciuent 

 decay. 



During the season of oviposition the females should be captured by hand in 

 the infested orchards. Their presence can be told by the newly girdled twigs. 

 " If the twigs are gathered and stored each year until about the first of July, 

 then burned, all the twig girdlers contained in them will be destroyed, and 

 meantime the egg parasites and probably some of the larval parasites will have 

 escaped." 



A bibliographical list of 18 references is appended. 



Corn and cotton wireworm (Horistonotus curiatus), W. A. Thomas (South 

 Carolina Sta. Bui. 155, pp. 3-10, pis. 7). — This preliminary report is based upon 

 investigations conducted in 1910 in cooperation with the Bureau of Entomology 

 of this Department, In Colleton County, where the greatest loss occasioned 

 by wireworms is found, an area of about 16 square miles is said to be infested. 



The first complaints of injury by this pest were received in the fall of 1907. 

 It apitears to be a very general feeder, attacking practically all of the farm 

 crops examined, including corn, cotton, cowpeas, oats, rye, peanuts, and tobacco. 

 The injury to cowpeas is occasioned by the small worms cutting off the feeding 

 roots as fast as they appear. The injured plant throws off numerous small 

 rootlets along the affected root and these in turn are cut off by the worms. 

 As the attack becomes more serious the plant 'ceases to grow and by the first 

 of June the root system has become a roll of short stubby roots and thickly 

 matted rootlets, clustering closely about the main stalk. The plants mature 

 at about one-half the normal size and usually without making any grain. 

 In many cases they are killed outright by the first attack. 



The wireworms have not been observed boring into the stalk or roots of corn. 

 Oats and rye seem to be attacked in the same way as corn, but the loss of roots 

 does not seem to affect these plants so vitally. " Cotton and tobacco are also 

 similarly affected. The tender feeding roots are clipped off, and the plants die 

 of starvation. In tobacco this occurs soon after the plants are transplanted 

 to the field and before they are thoroughly established in the soil. Very often 

 the young cotton plants do not reach the surface of the soil before being killed 

 by the wireworms. In peanuts the wireworms cut off many of the feeding 

 roots, seriously checking the growth of the plant, and when the nuts are formed 

 in fall these are bored into and the kernel destroyed. These worms have been 

 found working in the fruit of peanuts as late as October 21." 



The eggs are deposited in the spring and the larvae hatching out feed through 

 at least the two following summers, arriving at maturity in late spring or 

 early summer. The adults appear to emerge late in the summer or fall and 

 oviposit the following spring. 



The most serious injury to corn appears to be caused from May 15 to June 1, 

 that to cotton from the time it begins to come up until it has 3 or 4 leaves. In 

 oats and rye the attack begins in the fall while the grain is very small and 

 continues more or less throughout the winter and until it matures. 



In view of the fact that the injury is confined to plants growing in light 

 sandy soil decidedly deficient in humus, the remedial experiments conducted 

 aimed at supplying humus to the soil and the stimulation of plant growth early 

 in the spring. Experiments were conducted on 4 farms, a 5-acre tract on each 

 being laid out into 10 plats and planted to corn. It was found on April 28 

 that on plats containing growing rye from the previous fall's sowing practically 

 no worms were about the young corn plants, although thousands had collected 

 about the growing rye and were rapidly destroying the root system. On plats 

 without rye the corn was being badly attacked by the wireworms, about 40 



