385 



habits. Epitrimerus pijri (pear-leaf rust-mite) hibernates under the 

 bud-scales and causes a dry, rusty appearance of the foliage. Sulphur 

 sj)rays are recommended against it. Schizura concinna (red-humped 

 caterpillar) causes defoliation of portions of the pear-tree. The 

 larvae can often be found in the evening or early morning clustered 

 on a twig, and the removal of this will perhaps destroy the whole 

 colony. A lead arsenate spray should be used if necessary. PaJaeacrita 

 vernata (spring cankerworm) feeds on pear foliage ; nicotine or lead 

 arsenate sprays are recommended. Eriocampoides limacina {CaUroa 

 cemsi) (pear slug) devours the upper surface of the leaves and may 

 completely defoliate the tree. Eggs are laid just beneath the epidermis 

 and the larvae begin their attacks in May. When full-gro\\m they 

 pupate in the soil and emerge for a second generation after mid- 

 sunmier. Trees sprayed early ^^^th lead arsenate are seldom attacked, 

 but if the second generation appears, a nicotine or other contact 

 spray should be used, making two applications at an interval of 

 about a week. Dusting is also effective owing to the sliminess of the 

 larvae, which causes the dust to adhere and finally results in death. 

 Under the heading of insecticides and fungicides, a list of contact 

 and poison sprays, fumigants and repellents, is given, and many 

 formulae for the control of the above-named and other pests of 

 pear-trees are detailed. An ingenious chart is appended, showing 

 at a glance those insecticides and fungicides that may be mixed 

 with safety, as well as those that form dangerous or doubtful 

 combinations. 



BoDKix (G.E.). Report of the Economic Biologist. — Brit. Guiana Dept, 

 Sci. d' Agric, Rept. for the Year 1910, Georgetoicn, 10th May 1917, 

 U pp. [Received 11th July 1918.] 



On sugar-cane, the troublesome pest known as the giant moth 

 borer [Castnia licus] is now well under control, occasional sporadic 

 outbreaks being due to neglect in destruction of the insect. With 

 regard to the two smaller moth borers [Diatraea canelhi and D. sacclia- 

 ralis], control measures are not undertaken with sufficient thorough- 

 ness and consequently the position is far from satisfactory. The 

 main points in control are the careful selection of iminfested tops 

 for planting, regular and thorough cutting out of infested parts from 

 yoimg canes, breeding and distribution of parasites in conjimction 

 with a proper method of egg-collection, the super\asion by a trained 

 individual employed solely on this work, and the regular prosecution 

 of all such work throughout the year 



Rubber has chiefly suft'ered from the effects of the South American 

 leaf disease ; trees so attacked are frequently destroyed by termites, 

 notably Eutermes costwicensis. An amended list of rubber pests 

 includes the hawk moth, Erinnyis eUo, L. ; the Orthoptera, Tropidacris 

 coUaris, StoU, and Osmilia jiavolimata, DeG. ; the ants, Atta cephalotes, 

 L., and A. {Acromyrmex) octospina, Reich. ; the bug, Empicoris 

 variolosus, L. ; the Coccids, Asterolecanium sp., Vinsonia stellifera, 

 Westw., Saissetia nigra, Nietn., Aspidiotus destructor. Sign., and A. 

 persomitus, Comst. 



Coconuts were severely damaged, as in former years, by the butter- 

 fly, Brassolis £opliorae, L. It was observed that the caterpillars, instead 



(C496) X 



