648 EXPERIMENT STATION RECORD. 



ENTOMOLOGY. 



Insects of the clover field, (t. C. Davis {Michigan Sfa. Bui 1W, 

 2)p. 41-04, fuj.s. 11, pL 1). 



Synopsis. — This bulletin consists of 2 parts, the first dealing with insects rtestrnctive 

 to clover, comprising 4 species attacking respectively the root, leaf, seed, and 

 hay; and the second giving brief notes on 8 species that are designated as 

 common bnt not destructive. 



Insect.s destructive to clover (pp. 41-58). — Illustrated notes ou tLe 

 appearance, life history, ravages, and treatment of the clover-root 

 borer {Hylastes obscurus), clover leaf weevil {FJnjtonomus pnnctatus), 

 clover-seed midge {Gecidomyia Icyuminicola), and clov^er hay worm 

 {Pyralis costalis). The clover-root borer made its appearance in the 

 State in 1889 and rapidly spread over the middle and southern por- 

 tions, extending west to Lake Michigan. The greater destruction has 

 been in the southern part, its progress being slower toward the north 

 owing to the sandy forest regions. A map is given showing its distri- 

 bution ill the State. Investigations sliow that the imagoes tlrst ai)pear 

 early in JNIay, and tlie latter part of the month begin de])ositiiig their eggs 

 in the galleries bored in the clover roots where they have hibernated. 

 The larvse begin to pupate abciut July, issuing as adults in the fall and 

 passing th»i winter in that state. Red clover and mammoth clover 

 suffer most severely, although alsike is also attacked. White clover 

 seems to be exempt. The plants are rarely attacked until they are a 

 year old. Experiments with nitrate of soda, muriate of potash, and 

 kainit, applying them at the rate of half a ton and a ton per acre, 

 were made, but the beetles were apparently unaffected, while the plants 

 were seriously injured and some of them killed. Plowing under in the 

 spring of the secoii'i year, or plowing in the summer and thus expos- 

 ing the roots and young larvte to the sun, are suggested as the only 

 remedies at present known. 



The clover-leaf weevil is found in all parts of the State except the 

 northern, and has dime considerable damage. This season the pest was 

 destroyed in great numbers by a fungus disease [Enrpum sphcvro- 

 sperma). This rapidly killed the larva', which before dying crawled up 

 blades of grass and coiled themselves around the tips. In one instance, 

 cattle feeding upon such grass were rendered sick, though no serious 

 result ensued. A report on this fungus attack, by G. F. Wlieeler, is 

 included. 



The clover-seed midge is considered the most dangerous enemy of 

 the clover crop in the State, the flies depositing their eggs over the 

 clover head before the florets open, and the maggots crawling into the 

 flower tubes and making their way into the iorming seed. The eggs 

 for the first brood are laid in May, and for the second in July. Mam- 

 moth and common red clover are most attacked, alsike not being 

 molested. Pasturing clover fields through the spring and early sum- 



