612 



generally begins about two days after emergence, as many as 117 

 eggs being laid by one female. Adult life apparently lasts three or four 

 weeks. Some of the pupae spend two winters in the soil, thus making 

 a two-year life-cycle. The best time for the application of mercury 

 bichloride is when European plums are in full bloom, or when 

 American plums have just begun to blossom ; a second application is 

 given seven days later. For radishes and seed-beds of cabbage or 

 cauliflower, the second application should be made not more than 

 five or six days after the first. 



For control of the onion maggot [Hylemyia antiqua, Meig.] there 

 is much doubt as to whether poison baits or trap crops are the better, 

 and unfortunately the season-'s results were inconclusive ; further 

 trials will be made. An effective remedy for the tarnished plant-bug 

 [Lyguspratensis, Fall.], which is the cause of heart-rot in celery, is a dust 

 mixture of 20 parts Bordeaux (11 per cent.), 30 parts lime, 20 parts 

 sulphur and 30 parts tobacco dust. This should be dusted thoroughly 

 into the hearts of the plants once each week. Care must be taken 

 to get a suitable machine for this work. 



McLaine (L. S.). Insect Legislation in Canada. — Scientific Agric, 

 Ottawa, iii, no. 2, October 1922, pp. 51-54. 



This is a brief review of the Federal legislation at present in force 

 in Canada. The difficulties that would arise if legislative control 

 had to be extended to some basic commodity such as wheat or rice 

 are indicated. Inspection and treatment should be carried out, if 

 necessary, previous to shipping. The fact that common minor pests 

 in one country may be major pests in another is emphasised, and 

 exporters should endeavour to keep their premises free from such 

 insects. Canada is in a fortunate position, as she is not Hable to the 

 attack of foreign pests originating in the tropics, and unfortunate, 

 in that she has not the diversity of climate of the United States, 

 which permits the propagation of sufficient quantities of nursery stock 

 to meet internal needs. 



Brittain (W. H.). The Adult Habits of the Apple Sucker {Psyllia mali, 

 Schmidberger).— Scjt^«/j)^c Agvic, Ottaiaa, iii, no. 2, October 1922, 

 pp. 59-64, 3 tables. 



The relative activity of the adults of Psylla [Psyllia) mali, Schmidb. 

 (apple-sucker) is dependent on temperature and sunlight ; under 

 certain conditions they remain immobile for considerable periods, 

 particularly at night. They show a tendency to cluster together on 

 the lower surfaces of the leaves, but they do not feed as extensively 

 as the nymphs. The number of females increases in proportion to 

 that of the males as the season advances. 



In 1921 there was a noticeable diminution in the number of insects 

 in infested orchards in the third week in June for a month, when their 

 numbers began to increase again. On 1st August they were fairly 

 numerous on trees near orchards, diminishing rapidly as the distance 

 increased. The relative abundance of the insect at various periods 

 and on various trees is recorded. On 9th August the infestation on 

 apple trees had increased 100 per cent., with a reduction of 12 per cent, 

 on forest trees. On 21st August there was a reduction of 16 per cent, 

 on apple trees, but during the same period there was a much greater 

 proportional decline on forest trees. This reduction continued until 



