PREVENTING 0VIP0S1TI0X OF THE MOTH. 
125 
corded here to show that this suggestion, which, theoretically, looks 
plausible enough, is practically beset with great difficulties. We quote 
the following paragraph from Mr. Software's report ou experiments 
made at Selma, Ala. : 
While experimenting with decoctions and extracts of various plants, and knowing 
that the moths were ovipositing at the time, I tried the following three substances, 
with a \ir\v to ascertain whether they rendered the plant sufficiently distasteful to 
the moth to prevent her from ovipositing: 1. Infusion of Ailanthus leaves; 2. in- 
fusion of Walnut haves; 3 decoction of Iloarhound. The first I selected without any 
special reason, being influenced only by the universal belief in its efficacy ; the second 
because 1 knew by experience that it rendered the leaves distasteful to the worms; 
the third, on account of its most powerful and unpleasant smell. 
The application of the three substances was made very easily, as the moths ovipos- 
ited at this time (September 5) with preference on the leaves of the young shoots 
arising from near the roots of the plants. Three small shoots, each on a ditferent plant, 
were then examined for eggs, and, after removing these with a knife, the infusions 
were plentifully applied so that each leaf was fairly drenched from both sides. 
(Selma, Ala., Sept. 5.) 
Examination on the ?th of September shows that none of my decoctions had the 
slightest effect, the number of eggs laid on the three shoots being quite considerable, 
and apparently not less than on other shoots not treated with any substance. There 
was a heavy shower yesterday, hut the leaves being sprinkled on both sides, the rain 
could not have washed away every trace of the decoctious. 
Observations in the held seem to show that common road dust could 
possibly be utilized to prevent oviposition of the moth. Mr. Stelle says, 
in one of his letters from C alvert, Tex.: 
A much traveled road runs east and west through the field; on the south side of it 
the cotton is badly eaten by WOUM, w hile for 40 feet along the north side it does not 
stent to have been much disturbed. I investigated for the cause of this exemption, 
and found it to be the result of a south wind blowing the dust stirred up in the road 
over the plants. It seemed to have at h ast retarded the work of both Boll and Cot- 
ton Worms. 
Mr. Schwurz, while Speaking of those spots in cotton fields which had 
escaped the general destruction by the worm in August, 1880, says : 
The outside row or rows of a field are very often exempt, sometimes even to a re- 
markable degree, but by no means always. In some instances this immunity maybe 
due to the direct influence of the road dust that thickly covers the leaves, but it oc- 
curs also where there is no road, and consequently no road dust, and where, therefore, 
another explanation is necessary. I fail to find any sat isfactory explanation, unless, 
perhaps, in such cases the outside rows grow under conditions less favorable to the 
plants, which thus have less attraction to the moth. 
Mr. Stelle himself noticed later the exemption of the outside rows of 
cotton fields. He writes in his diary, September 3, 1880: 
I have noticed in fields that the plants growing adjacent to open spaces, as along 
roads, even though but little traveled, are more or less exempt from the working of the 
worms. In the midst is about one-fourth of an acre in sweet potatoes, rank-growing 
and clear of weeds. For about the width of two rows around the patch the cotton is 
scarcely touched, while everywhere else it is completely trimmed. 
I have seen a similar case along the side of a patch of peas (Dolichos) where the 
exempt rows were several hundred yards in length. 
Similar facts have often come under our notice and are quite com- 
monly observed. 
