Caesar (L.). Insects as Agents in the Dissemination of Plant Diseases. 

 —49th Ann. Repl. Entom. Soc. Oniario 1918; Toronto, 1919, 

 pp. 60-66. [Received 28th October 1919.] 



Many fungus, bacterial and physiological diseases are disseminated 

 by insects ; those here discussed include ergot of rye {Claviceps 

 jmrpurea) transmitted by flies ; downy mildew of lima beans 

 {PhyfopJitkora phaseoli) by bees ; chestnut blight {Endothia parasitica) 

 by the Cerambycid, Leptostylus macula; white pine blister ru^t 

 {Cronartium rihicola) by gipsy moth [Lymantria dispar] larvae ; 

 gooseberry twig disease, which enters through the wounds apparently 

 made by a cambium miner, Opostega nonstrigeUa ; canker on apples 

 {Leptosphaeria coniothyrium), encouraged by attacks of Oecanthus 

 niveus, the same fungus being introduced into raspberry canes by 

 0. nigricornis. Plagionotus speciosus (maple borer) causes wounds 

 tlirough which heart-rot enters ; the weevil, Crypforrhynchus lapathi, 

 transmits European poplar canker {Dothichiza populnea). Although 

 brown rot of fruits {Sclerotmia cinerea) is not directly insect-borne, fruit 

 attacked by the plum curculio [Conotrachelus nenuphar] and cherry 

 fruit- flies [Rhagoletis] are more susceptible to it. 



The insect-borne bacterial diseases include : cucumber wilt {Bacillus 

 tracheiphilus), transmitted by Diahrotica vittata (striped cucumber 

 beetle) and D. duodecimpunctata ; and pear blight {B. amylovorus), 

 probably disseminated by ants. 



Other diseases include the mosaic diseases of sweet peas, tobacco, 

 and cucumber transmitted by Aphids ; curly top of sugar-beets 

 spread by Eutettix tenella (beet leaf-hopper), and spinach blight by 

 Macrosiphum solanifolii, Myzus [Rhopalosiphum) persicae and Lygus 

 pratensis (tarnished plant-bug). 



HucKETT (H. C). The Cabbage Root Maggot {Chortophila brassicae).— 

 49th Ann. Rept. Entom. Soc. Ontario 1918; Toronto, 1919, 

 pp. 67-69. [Received 28th October 1919.] 



Recent experiments with regard to the control of the cabbage root 

 maggot, Phorhia {Chortophila) brassicae, show that the application of 

 corrosive sublimate is more efficacious than the use of tarred felt discs. 

 This poison should be applied directly to the roots by means of a 

 watering can at a strength of 1 part to 1,000 parts of water or 1 oz. 

 to 50 pints of water. The first application was given four days after 

 the plants were set out and this was followed by three more at intervals 

 of seven days. It has not yet been tested for radishes, and further 

 investigations are necessary to determine the best time for applications 

 and the strength which should be used for this crop. 



LocHHEAD (W.). Some Chapters of the early History of Entomology. 



—49th Ann. Rep. Entom. Soc. Ontario 1918 ; Toronto, 1919, 

 pp. 69-81. [Received 28th October ] 919.] 



The evolution of entomological knowledge from the earliest days is 

 reviewed. Mention is made of the great iiisect ecologists and system- 

 atists, and the earlier systems of classification of insects are described. 

 The beginnings of parasitic work and natural methods of control are 

 also dealt Avith. 



