DAMAGE 



White-fringed beetles do not usu- 

 ally cause uniform damage over 

 large continuous areas. Crop injury 

 may range from just a trace in one 

 part of a field to destruction of a 

 crop in a nearby field. 



In general, plants with main roots 

 (tap roots) are damaged more se- 

 ^•erely than those with fibrous roots. 

 The larvae may sever the main root 

 while they are feeding. On root 

 crops, such as potatoes, carrots, and 

 turnips, they buri-ow directly into 

 tlie roots, and destroy the market 

 value of the crop. 



A number of factors may influ- 

 e]ice the intensity of an infestation. 

 The beetles are more abundant — 

 and damage is greater — in well- 

 drained, sandy loam than in heavy 

 clay soils. An unusually dry sum- 

 mer ma}' retard the beetle's develop- 

 ment. A heavy rainfall, which 

 saturates the soil for about a week, 

 kills manv vounjr larvae. 



DEVELOPMENT 



The white-fringed beetle passes 

 through the following stages : 

 Adult, egg. larva, and pupa. It 

 usually produces only 1 generation 



a year, and spends all but about 3 

 months in the soil. 



Adults begin emerging from the 

 soil in early May and continue to 

 do so until early fall, the exact time 

 of emergence dependin<x on the lo- 

 cality. They are dark gray, are 

 about vie ii^<^^^ long, and have a 

 white fringe, or band, along the 

 outer edges of the body. They 

 feed on margins of leaves for sev- 

 eral days and then begin laying 

 their eggs. (All adults are females 

 and are capable of laying fertile 

 eggs.) 



The eggs are laid in masses on 

 sticks, and other debris lying on 

 the soil; on stems of plants: or in 

 the soil, usually near the roots of a 

 plant. They are covered with a 

 sticky substance that holds them to- 

 gether and also to the object on 

 which they are deposited. 



An egg mass usually contains 11 

 to 14 eggs, but some masses have 

 up to GO eggs. Each egg is about 

 1^5 inch long. 



How many eggs an adult lays and 

 how fast she lays them depend upon 

 the kind of plant on which she feeds. 

 In tests conducted by entomologists 

 at Florala, Ala., beetles that fed on 

 peanut foliage laid an average of 

 1600 eggs (one beetle laid 3,258 

 ea'g^). but those that fed on o-rasses 



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Larval 

 damage 



to 

 cotton 



506202°— 59 



