36 COTTON 



all due to the organism known as Bacterium malva- 

 cearum. Boll rot is first noticeable as a small, dark- 

 brown patch on the boll at a point near the peduncle. 

 If it begins some time before ripening takes place the 

 boll does not open and the immature fibre decays, but 

 if it commences later only a portion of the boll is 

 affected and a certain amount of cotton may be 

 produced. 



Insect Pests. The cotton plant is attacked by a 

 great many different insects, some of the more 

 important of which are the boll-weevil, boll-worms, 

 cotton worms, cutworms, cotton aphis, cotton 

 stainers, and locusts. 



Cotton Boll-Weevil. The most serious insect enemy 

 of the cotton plant is the cotton boll-weevil (Antho- 

 nomus grandis). Its original home was Mexico, where 

 it caused considerable damage. In 1892 it entered 

 Southern Texas, and since 1894 has travelled at the 

 rate of from forty to seventy miles a year, and is still 

 extending. The pest is now prevalent in the States 

 of Texas, Louisiana, Mississippi, Alabama, Arkansas, 

 Oklahoma, Western Florida, and Georgia. The total 

 area infested was estimated in 1913 as about 296,300 

 square miles, comprising no less than 47 per cent, of 

 the whole cotton acreage of the United States. The 

 pest has now made such progress that nearly the 

 whole of the cotton-growing area of the country has 

 been invaded. The annual loss occasioned by the 

 depredations of the insect is enormous, but fortunately 

 the pest is confined to Mexico and the United States. 



The boll-weevil is a small grey or brownish beetle 

 about one quarter of an inch long. It remains on the 

 cotton plant until the end of the season, and then 

 hibernates, finding a home in a sheltered situation, 

 such as is afforded by hedges and haystacks or by 

 grass, weeds or rubbish lying on the ground. With the 

 advent of spring, the weevil emerges from its winter 

 quarters and again betakes itself to the cotton plant. 

 The female insect eats into the boll and so makes a 

 cavity in which she lays her eggs. The egg hatches 

 in about three days, and a whitish grub or larva 

 emerges, which immediately begins to feed on the 



