Ill 



Illinois Natural History Survey Bulletin 



Vol. 27, Art. 2 



those areas declined steadily. Conversely, 

 in certain dry, sandy areas which were 

 broujjht under irrijjation wireworm dam- 

 a<je increased. 



As le^^ume production increased, the in- 

 sect pests of lejiumes tended to increase. 

 Notable examples are the clover leaf wee- 

 vil, clover root borer, pea aphid, bean leaf 

 beetle, sweet clover weevil, green clover- 

 worm, and spotted alfalfa aphid. 



Two attempts to initiate and promote 

 the commercial production of sunflowers 

 in Illinois were doomed to failure largely 

 because of the overwhelming insect prob- 

 lems encountered when many species from 

 the native sunflowers swarmed onto the 

 cultivated varieties. In contrast, we find 

 that in extreme southern Illinois cotton 

 production survives in a rather unfavor- 

 able climate, and under other adverse 

 conditions, largely because important cot- 

 ton insects are absent and planters are 

 spared the cost of extensive insect control 

 measures. 



Pests of Forest and Shade Trees 

 and Ornamental Plants 



Efi'ective control measures are now 

 available for most of the insect pests of 

 trees and ornamental plants; yet man 

 seems to have little success in combating 

 these insects. It is not that these insects 

 are new or relatively unknown, for the 

 majoritv of these pests were recognized 

 and well known prior to 1850. The bark 

 lice (scale insects), round-headed borers, 

 flat-headed borers, bark beetles, bagAvorm, 

 walnut caterpillars, cankerworms, and 

 the 17-year locusts are frequently men- 

 tioned in the Illinois entomological writ- 

 ings of a century or more ago. Chemical 

 control measures were not available at 

 that time, but some of the proposed meas- 

 ures were partiallv effective and more or 

 less practical. Mechanical barriers and 

 sticky bands were used to control the can- 

 kerworms, sometimes successfully and 

 sometimes not. It now appears that im- 

 proper timing and failure to recognize 

 the difference between the spring and the 

 fall cankerworms accounted for most of 

 the variation in control. Hand picking 

 was often mentioned and, according to re- 

 ports, if done diligently it was effective 

 in controlling the bagworm, the walnut 

 caterpillars, and the tent caterpillars. 



Hand grubbing, with a wire or knife, was 

 considered an effective means of control- 

 ling several species of borers. Several 

 types of soapy washes were proposed for 

 the control of aphids and scale insects, but 

 perhaps the most positive, wisest, and 

 most ingenious of all recommendations 

 was that proposed by Dr. Mygatt (1855: 

 516) in his essay on the bark louse: 

 "Whether you choose a seedling or graft, 

 by all means transplant a clean tree, 

 if you have to occupy hours and even days 

 in examining and clearing j^our trees 

 from every scale." 



As insecticides and means of applying 

 them were being developed for use on 

 various agricultural crops, it was nat- 

 ural that most of them would be tested 

 to determine their potential usefulness in 

 controlling insects attacking trees. The 

 value of Paris green in controlling the 

 cankerworms was established at a very 

 early date. By 1910 lead arsenate, first 

 developed in 1891 for use against the 

 gypsy moth, was being recommended for 

 a variety of leaf-eating insects, and by 

 1925 high-powered sprayers, dusters, and 

 even airplanes had been developed and 

 were quite generally available for use in 

 treating both shade and forest trees. Nev- 

 ertheless, progress was slow; apparentlv 

 the weather and tree protection have 

 something in common — everybody talks 

 about them, but nobody does anything 

 about them. 



The average citizen who professes an 

 interest in and a love for trees is some- 

 times like the kibitzer who, at an active 

 poker table, talks a good game, but, for 

 reasons best known to himself, fails to put 

 his money on the line. In the past 2 years 

 in many Illinois communities, beautiful 

 landscape plantings, such as juniper, val- 

 ued at hundreds of dollars were rendered 

 unsightly and in many cases were killed 

 outright by the bagworm ; a dollar's worth 

 of malathion, or the old faithful, lead 

 arsenate, and 30 minutes' time could have 

 prevented any damage. In some commu- 

 nities there has been a wholesale loss of 

 elm, oak, and birch trees of inestimable 

 value and irreplaceable in less than 3 dec- 

 ades ; little evidence Avas available that 

 control measures were even considered. 



This seeming indifference in some com- 

 munities is partially offset by the genuine 



