222 



THE PEA THRIPS {KAKOTHRIPS R0BU8TU8). 



By C. B. WILLIAMS, B.A., F.E.S. 



{The John Innes Horticultural Inst if ul ion, M erf on, Surrey.) 



(With 12 Text-figures.) 

 CONTENTS. 



PAOE 



Introduction and history ....... 222 



Species and synonomy ......... 224 



Habits of adult. Appearance, sexes, pairing, parthenogenesis, flight, 



food, oviposition ......... 228 



The Egg 229 



Larval stages ........... 230 



Pupal stages ........... 235 



Distribution. British Isles, abroad ....... 23(5 



Nature of damage .......... 238 



Food plants 240 



Other thrips found on peas and beans ...... 240 



Natural enemies . . . . . . . . . . 241 



Effect of rain, soU, varieties, time of planting .... 242 



Control, sprays, rotation, soil fumigation 243 



Methods of collecting and breeding 244 



Summary 245 



Bibliography ........... 245 



History. 



Although no doubt damage has been caused to peas and beans for 

 many years by thrips, apparently the first record of such an occurrence 

 is found in 1871 when A. Miiller^ describes shortly, without however 

 mentioning any locaHty, an attack on peas, which was certainly due 

 to the species here discussed. 



In 1880 Westwood gives a much fuller account of an attack at 

 Oxford, with figures of the damaged flowers and characteristically 

 curled pods. He gives the name Thrips pisivora to the black-tailed 

 yellow larvae, which were in numbers on the damaged plants, under 

 the impression that they were the adult females, and only just mentions 



' All references will be fountl under aiitlinr and year in tlie iiibliou'iaphy at the end. 



