329 



Ehrhorn (E. M.). Report of the Chief Plant Inspector. — Ite'pt. for the 

 Bien. Period ending 31st December 1918, Territory of Hawaii Bd. 

 Agric. & Forestry, Honolulu, 1919, pp. 61-85, 3 plates. [Received 

 3rd June 1919.] 



An account is given of the work of plant inspection during the period 

 under review, and is summarised in tables. The new inspection 

 buildings, and particularly the fumigation huts, have given greatly 

 improved facilities for this work. Large consignments of wheat from 

 Australia infested with Rhizojjertha dominica (lesser grain borer) were 

 cleansed by fumigation. 



The following interceptions of insects are among those mentioned : — • 



Stigmaeus fioridanus (pineapple mite) from Florida, which, besides 

 the damage done in feeding, carries dangerous plant diseases that 

 gain access to the tissues of the leaves of pineapple through its punc- 

 tures ; Iridomyrmex humilis (Argentine ant), in the soil around 

 plants from California ; a Curculionid beetle from the roots of potted 

 plants, and Aleurodes citri on citrus plants from Japan. 



A copy is given of the rules and regulations of the Board of Agricul- 

 ture and Forestry pertaining to the Plant Inspection Division that 

 have been drawn up during the past two years, as well as all quarantine; 

 notices and other restrictive orders. 



FuLLAWAY (D. T.). The Corn Leaf Hopper {Peregrinua maidis, Ashm.). 

 — Hawaii Bd. Agric. Forestry, Honolidu, Div. Entom., Bull, 

 no. 4, 27th December 1918, 16 pp., 18 figs. [Received 3rd June 

 1919.] 



To growers in the Hawaiian Islands the control of the leaf -hopper, 

 Peregrinus maidis, Ashm., is a serious problem. This insect is closely 

 related to the sugar-cane leaf-hopper [Perkinsiella saccharicida], but 

 in Hawaii is found only on maize. In confinement it will oviposit in 

 stems of sugar-cane and Coix lachryma, but the nymphs apparently can- 

 not develop on these food-plants. When it is abundant on maize the 

 plant withers as if suffering from drought. The hoppers are distributed 

 mainly by flight, and also by hopping from adjacent fields and by 

 wind-dispersion. The eggs are deposited principally in the midrib on 

 the upper surface of the leaves, from one to four being loosely packed 

 in each cavity. These hatch in summer in 9 days, but in cold, dry 

 weather may take 14 days. The nymphal stage lasts from 15 to 21 

 days, during which 5 moults occur. Dimorphism is frequently foimd 

 among the adults, both long and short winged forms occurring. Mating 

 and oviposition take place as soon as the adult insects appear, each 

 female depositing an average of 200 eggs. The life-cycle occupies 

 about one month, and as maize plants require from 100 to 120 days 

 to mature, it is obvious that several generations of hoppers may be 

 present on the plants simultaneously. Artificial remedial measures 

 have not been applied to P. maidis to any great extent. It might be 

 possible to reach the nymphs, which are the most injurious stage, 

 with a kerosene or nicotine spray, but it would have to be weak to 

 avoid injury to the plants and might seriously interfere with the egg- 

 parasites. Hopperdozers also might be successful. The most effective 

 checks so far have been insect parasites and judgment on the part of 

 the grower as to time of planting. 



(C577) B 



