320 



P. gossypiella is one of the most formidable cotton pests of Korea^ 

 the first brood destroying the flowers and the second the seeds. A& 

 regards remedial measures, advantage may be taken of the dislike of the 

 larvae for sunshine by collecting the bolls and exposing them to it. 

 Ploughing in the winter also destroys some of them. Burning infested 

 buds or bolls and submerging the seed in water so as to detect 

 infested examples may sometimes be employed. 



Tetranyehus bimacidatus, Harv., appears at the end of June in the 

 cotton field, and attacks the plants which are then five or six inches 

 high ; 12 or 13 generations occur in a year. Females that have hiber- 

 nated oviposit at the end of February on weeds, and the resulting 

 adults, after passing through three nymphal stages, attack the cotton. 

 Eeproduction is both sexual and parthenogenetic. Parthenogenesis is 

 most marked in summer, though it also occurs in spring and autunm> 

 while sexual reproduction is continous throughout the year. There is 

 no difference in the morphology and habits of individuals produced in 

 the two manners, though those })roduced by parthenogenesis are 

 exclusively males. Males are however usually less numerous than 

 females. Oviposition begins, 3 or 4 days after pairing in spring, on 

 the same or the next day in summer, and after 2 or 3 days in autumn. 

 A female lays from 50-180 eggs and dies two or three days after ovi- 

 position. In hot, dry seasons oviposition is very vigorous ; in cool, wet 

 seasons the opposite occurs, so that in rainy years the outbreak is 

 much reduced. For hibernation, the mite leaves the cotton, shelters 

 among weeds near by and becomes inactive. Males are readily killed 

 by cold, so that those that survive the winter seem to be nearly all 

 females. 



This mite may attack the leaves of cotton to such an extent as to 

 cause defoliation: and the ultimate death of the plant. It also attacks 

 beans. Burning of weeds near the cotton fields in winter, and of infested 

 stalks before this, is very effective. A 45 X solution of lime-sulphur 

 (35'^ Be.) is sufficient to kill this pest in half-an-hour. 



LEGISLATION. 



New Plant Inspection Rule. — Hawaiian Forester and Agriculturalist^ 

 Honolulu, xvii, no. 3, March 1920, pp. 56-57, 70. [Received 

 10th May 1920.] 



The text is given of "Rule XXI — Division of Plant Inspection," 

 prohibiting, with penalties, the carrying of any white ginger plant, 

 fern plant or Spanish moss {Tillandsia usneoides) from one locaKty 

 to another throughout the Territory. In the case of the first two the 

 rule is directed against a recently discovered pest of the white ginger 

 plant [Pteroporus subtruncatus, Frm.] and against the Australian fern 

 weevil [Syagrins fulvitarsis] [R.A.E., A,viii, 191.] 



