202 



E. violae, Nal., causes curling of the leaves, and it was found that 

 beds manured with superphosphate and potash, and on which 

 ammonium sulphate had also been used, did not suffer. Rapid growth 

 seems to save the plants, otherwise removal of the attacked leaves is 

 the only remedy. Tylenchus devastatrix, Kiihn, was reported from 

 many districts, damaging rye in some places and, in the flower- 

 growing areas, attacking especially hyacinths. Gallonia candicans 

 (summer hyacinth) also suffered from the pest. Heterodera schachtii,. 

 Kiihn, was found on sugar-beet. 



Dk Bussy (L. p.). Dlerkundige afdeeling. [Zoological Section.]— 

 Meded. Deli Proefstat., Medan, viii, no. 7, September 1914, 

 pp. 215-223. [Received 5th December 1914.] 



This is a section of the annual report of the Deli Experiment Station 

 for the year ended 1st July 1914. The great drought and the failure 

 of the usual rainstorms which generally kill great quantities of eggs 

 and caterpillars made the year 1914 a serious " caterpillar " year in 

 many places. Just as in 1912-13, Prodenia litura was much more 

 prevalent than Chloridea {Heliothis) obsoleta, perhaps because the latter 

 is more readily controlled by insecticides, whereas Prodenia can only 

 be kept down by destroying the eggs and caterpillars. Nevertheless, 

 in certain localities, Chloridea proved a veritable plague and Prodenia 

 was entirely absent ; it has been observed before that, in certain cases, 

 one species seems to exclude the other. Phytometra {Plusia) was 

 always less nimierous than either of the above, but in the past tobacco 

 season it was found in some numbers on poor, exhausted land and in 

 the drying sheds. It is noted that the Prodenia caterpillars come out 

 of the earth on the floor of the drying sheds and are not carried there 

 with the tobacco, as is the case with Phytometra. Young tobacco was 

 severely attacked in some places by " toa-toh," Phthorimaea [Lita), 

 and, in spite of the rain, whole plantations were destroyed. Tobacco 

 suffered more than any other crop, although covered with mosquito 

 netting as soon as planted out. Even when the plants in the 

 nursery were quite free from this pest, in from one to three 

 weeks full-grown caterpillars were to be found on almost every 

 stalk. A possible wild solanaceous food-plant was found, on which 

 caterpillars very like those of Phthorimaea were feeding. These 

 were bred out and a moth also resembling the imago of Phthorimaea 

 resulted, but, contrary to experience with that species, the adults 

 did not breed, and it is regarded as a closely allied species or a variety, 

 as it would not oviposit on tobacco. The idea that if tobacco cultivation 

 were abandoned for a time this pest would be starved out is not 

 practical, as there is too much wild tobacco outside the plantations 

 and especially on those which, for rotation, are planted with rice, 

 which has quite wrongly obtained a bad name as a food-plant of this 

 pest. A composite plant known as " sendrong " is feared by the planters 

 because this moth may be found in its heads, but this fear is declared 

 to be baseless. The hawk-moth, Protoparce convolvuU, a host of Tricho- 

 gramma, was only reported twice in the neighbourhood of Medan, 

 whereas in 1912-13 it did enormous damage all along the East Coast 

 of the island. Belippa, also a serious pest of the previous year, was 

 hardly noticed. The breeding of Trichogramma pretiosum in the eggs of 



