252 



THE AMERICAN ENTOMOLOGIST. 



road over the plants. It seems to have at least 

 retarded the work of both boll and cotton worms. 

 —J. P. Stelle, Calvert, Te.x. 



Pyrethrum Roseum.— The only species of its 

 genus which gives a good, effective insect pow- 

 der is nowhere cultivated, but grows wild in the 

 basal-alpine zone of our mountains (6-8,000 feet). 

 I intend to again visit the mountains shortly, and 

 shall try my best to comply with your request, 

 and think to send you, in September, about 

 one pound of the seed, collected by myself. 

 Whether the cultivated plant will have the same 

 excellent properties as the wild one, I cannot 

 decide. The insect powder of the market is re- 

 cently much adulterated, but the genuine, pure 

 powder of Pyrethrum roseum is most e.\cellent 

 for every injurious insect. This I can vouch for. 

 The plant is perennial, so that, if you succeed in 

 cultivating it, the produce is plentiful.— Dr. 

 Gustav Radde, Tiflis. 



Boll Rot. — I send you by to-day's mail a small 

 box of cotton bolls as a sample of the rot which 

 is now doing great damage to the cotton crop in 

 this section. This species of rot is known among 

 old planters as the "greasy" rot, and is a sequel 

 or result from either very wet or dry summer. 

 This year it is the result of extreme wet weather. 

 It is called "greasy" rot from the first appear- 

 ance of the little spots which show themselves on 

 the bolls. These spots soon turn brown, and 

 the whole boll is soon rotted. It is principally 

 the top crop which rots. For several seasons I 

 have thought that this rot was caused by an in- 

 sect puncturing the boll for the purpose of de- 

 positing eggs. When the bolls are fullv rotted, 

 quite a number of worms— small, white, with very 

 hard heads— are found in them. It may be that 

 these worms are a species of maggot deposited in 

 the boll after it commences to rot. The rot may 

 be a kind of mildew, [i.] 



The Cotton Worm has behaved very singularly 

 in this region, having been sufficiently numerous 

 early in August to have propagated sufficiently 

 to destroy the cotton crop by September 10 ; but 

 they have gradually decreased, in spite of favor- 

 able rainy weather, and now there are very few 

 of them. The birds and ants are very numerous, 

 and also the little tly which destroys the eggs! 

 [2.] Prof. Barnard found so little chance for 

 observation here that he went up the river.— P. 

 S. Shields, Vidalia, La., Sept. 10, 1880. 



[i-— There islittle question but that this kind of 

 rot proceeds from a puncture or the gnawings of 

 the Boll Worm, as Prof Stelle has recently proved. 

 Your specimens corroborate this fact. Both the 

 fungus and the maggots are after efl^ects. 2. — 

 The natural enemies, no doubt, kept the worms 

 in check.] 



London Purple.— Most of the farmers out here 

 use Paris Green, but I persuaded several to try 

 London Purple, and all report excellent results, 

 and I used it m3'self upon several kinds of bugs 

 and on the Army Worm. I like it much better 

 than Paris Green, and it works better in my case 

 —does not settle so quick. I think it is bound 



to take the place of Paris Green, which is being 

 adulterated so much that it is almost impossible 

 to get the genuine. I shall recommend it highly 

 next year.— S. H. Fox, St. Louis, Mo., Sept. 20. 

 Effect of Pyrethrum on Boll Worm.— Aug. 

 27th— Sprayed extract Pyrethrum (Buhach) on 

 stalk of cotton containing three small Heliothis: 

 one of these was partially in the ball, the other 

 two were on the flowers. The extract was made 

 by taking half a tin package of Milco's Buhach, 

 introducing it into a glass flask, adding half 

 gallon of 95 per cent. Ethyl Alcohol, allowing it 

 to stand corked for (24) twent3'-four hours ; I 

 then introduced a tube of glass thirty-six inches 

 long and one-fourth of inch in diameter into the 

 cork, and then subjected the flask and con- 

 tents to the gentle heat of a water bath, never 

 allowing the heat to reach the boiling point of 

 alcohol. This gentle heat was continued five 

 hours and the flask then set aside to cool. When 

 cool, before using, the liquid was diluted with 

 twenty times its volume of water. In five minutes 

 after the application of the diluted extract to the 

 stalk by means of a sprinkler, the three worms 

 fell to the ground and rolled over and over as if 

 in pain, at times they attempted to crawl off but 

 would be siezed with convulsions. They did 

 not get far from the stalks from which they fell, 

 but lived more than six hours, dying sometime 

 during the night. 



2. Sept. 17th — In the following experiment I 

 used some of the same extract spoken of in pre- 

 ceding experiment. The quantity this time was 

 half pint extract to five pints water. I selected 

 a spot in the cotton field where Aletia; were toler- 

 ably numerous. There were three stalks of 

 cotton growing close together, and the vines of 

 Morning Glory had densely intertwined them- 

 selves with these three plants, making the foliage 

 very thick and hard to penetrate. I caught a 

 number of .Aletia: from other stalks of cotton and 

 put them on these until I could count 120. In 

 all this time neither I nor either of the gentlemen 

 present to witness the experiment noticed a 

 boll worm (Heliothis). I used a small fountain 

 pump made by Eumsey & Co., Seneca Falls, N. 

 Y. We sprayed the diluted extract over three 

 rows for about twenty feet, throwing more upon 

 the three plants mentioned than elsewhere. 

 Whilst the spray was falling upon this thick 

 foliage I closely watched its eflfect : to ni)' sur- 

 prise a large Heliothis appeared on a leaf seem- 

 ing to be bewildered and making rapid exertions 

 to get off. On examination I found it had come 

 from the interior of a full grown boll on which 

 it was feeding ; the orifice it had cut was on 

 the upper side, and I suppose some of the fine 

 spray passed through the orifice, and disturbing 

 it in its excavations, caused it to come forth. 

 Soon after it appeared it crawled on a leaf which 



