go 



NATURAL ENEMIES. 



Two new parasites of this webworm were reared during the year 

 and have been identified by Mr. Ashmead as Meteorus >mlgaris Cress, 

 and Temducha (JPorison) macer. Cress. 2 .. both hymenopterous. The 



former, an Ichneumonid, was reared in September from material 

 received from Auburn. Ala. : the latter, a Braconid, issued during the 

 latter days of July from larvae received from Charleston. S. C. 



The Tachinid parasite Exorista pystt Walk., previously mentioned as 



an enemy of this webworm. was reared October 6 from the South 

 Carolina lot. received in 1896, and recorded in Technical Series No; 7. 

 of this Division, page II. although the host was not known at that time 

 by its specific name. An effort wa> made to ascertain the past year 

 if any new species of parasitic or predatory insects were useful in 

 destroying this webworm. but none of the several lots of larvae which 

 were sent from different localities and kept in our rearing jars for the 

 purpose were parasitized. It is quite probable that in the course of 

 time many of the various known parasites of other crucifer-feeding 

 caterpillars will be found to attack this webworm, but for this we may 

 have to wait perhaps for several years before parasitic or other nat- 

 ural enemies will be of any service as medium.- for its reduction. 



REMEDIES. 



At the present writing nothing new has developed in the line of 

 methods of control. It is suggested, however, that in view of the 

 unusual destructiveness of this insect that some such methods as are in 

 use against the striped cucumber beetle be employed, for example, the 

 planting of an excess of seed with the aim of afterwards destroying 

 those plant- which are injured by this webworm beyond redemption. 



Cabbage and turnip appear to be the favorite crop plants affected. 

 though collards and radishes are also attacked: and it seems probable 

 that these could be advantageously used for the protection of beets 

 and vegetables other than Cruciferse, which future observations will 

 probably show are affected by the insect. The trap crop should be 

 freely sprayed with Paris green, and the main crop could be sprayed 

 witl kerosene emulsion. Mr. Simon- write- that a mixture of kero- 

 sene oil and soap -prayed upon the plant- served as a deterrent against 

 the moth, but that they returned a- soon a.- the odor of the kerosene 

 had become dissipated. Kerosene emulsion properly prepared and 

 applied often enough to insure a permanent odor should be effective. 



One point must be emphasized if we expect to meet with success in 

 combating this insect, and this is that work must begin upon the first 

 appearance of the insects each season, as what is done then will very 

 materially affect injury for the entire year. Injury might be consid- 

 erably lessened if a practice were made of pulling up and destroying 



