435 



LuGiNBiLL (P.). U.S. Bur PIntom. Injurious Insect Pests of Cereal 



and Forage Crops of South Carolina. — loth or 16th Ann. Repts., 



1918 & 1919, S. Carolina Conwiiss. Agric. Comm. & Ind., 



Columbia, 1919 and 1920, pp. 113-115 and 217-219. [Received 



9th July 1921.] 



These notes, given in both of the reports, refer to insect pests in 



South Carolina in 1918. Blissus leucopterus, Say (chinch bug) was very 



destructive to maize in the northern part of the State. Laphygma 



fnigiperda, S. & A. (fall army-worm or southern army-worm) appeared 



in early Julv and damaged maize, lucerne and young sorghum. 



Diabrotica di(odccimpnnctata, 01. (southern corn rootworm) was 



iniurious to maize, but to a less extent than in the previous year. 



Mavetiola destfudcy (Hessian fly) has been reported, for the first time 



authentically, as damaging wheat in the northern parts of the 



State. Minor pests inchided Chaetocnenia sp. (flea-beetles), Prodenia 



ornithogalli, Gn. (cotton cutworm) and others. 



LuGixBiLL (P.). On the Biology of Aphis avcnae, Fab., in the South- 

 east, with Causes conducive to the Unusual Abundance of this 

 Species as well as Toxoptcra gmminum, Rond., during certain 

 Seasons. — 16th Ann. Rept. 1919, S. Carolina Commiss. Agric. 

 Comm. & Ind., Columbia, 1920, pp. 219-229, 4 figs. [Received 

 9th July 1921.] 

 During the outbreak of Toxoptera graminum, Rond. (spring grain 

 aphis) on oats in the south-eastern States in January-March 1913 

 [i?. .4.£"., A, vi, 468] Aphis avenae (oat aphis) was also present in 

 consideral^le numbers, and a good deal of information was obtained 

 regarding the latter species in the vicinity of Columbia, South Carolina. 

 The variation in length of life of individuals during the year is shown 

 in a graph ; the average longevity of individuals produced during the 

 summer months was about 22 days, increasing to 25 days for those born 

 in autumn, and 75 days for those produced in winter. The number 

 of young of the individuals constituting the generations are com- 

 pared in a graph. The average number of young per individual during 

 the summer months was about 33, and for the winter months 38. 

 In the year in question there were found to be approximately 24 

 generations in the course of a year. No oviparous fornis appeared 

 in this series. It is quite probable, however, that had the species been 

 kept in breeding condition, oviparous forms would have appeared 

 later on, perhaps in the autumn of. 1914. 



It has long been recognised that certain meteorological conditions 

 favour an unusual abundance of Aphids during certain seasons. It 

 has been suggested that during cool, wet springs the parasites and 

 other enemies of Aphids are held in check, while the Aphids continue 

 to multiply and will then outnumber their enemies when the weather 

 becomes warmer and all are active again. During such periods great 

 damage to crops is often done by the Aphids. In the middle-western 

 States the minimum temperature at which Aphids breed has been 

 fixed at 40° F., while parasites require a temperature of at least 56^ F. 

 In the south-eastern States outbreaks come somewhat earher. It is 

 the author's opinion that heavy rains at frequent intervals, instead of 

 being conducive, are a hindrance to an outbreak, as large numbers of the 

 Aphids, especially 3'oung forms, are killed by direct action of the rain. 

 This paper, without the graphs, was printed in the 15th Annual 

 Report for 1918. 



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