48 



of the stages varies considerably. The larval period occupies from 

 4 to 14 weeks and it is sometimes stated that the majority of the larvae 

 leave the galls in autumn, a few only remaining until March. In 

 opposition to this view are the results of observations made in 1914 

 and 1915, when specimens were received in which most of the galls 

 were still tenanted by larvae, none of which pupated before March. 

 The probable explanation is that a second and possibly a third brood 

 may arise in the late summer. The fact that the insects can pass the 

 winter as either larvae or pupae is of importance in considering means 

 of control. In addition to turnips, mustard, charlock, rape and cabbage, 

 including Savoy and Brussels sprouts, are attacked. Records of injury 

 have been received from most English counties and the insect is well- 

 known in France, Russia and Germany. 



The following methods of control are recommended :• — ^(1) Where 

 the turnip crop is attacked, the turnips should be consumed as soon 

 as possible so as to destroy the larvae before they leave the galls. 

 (2) If a cabbage crop is attacked, the stumps and roots should be 

 burned. (3) After an attack, the land should be deeply ploughed, 

 and in the case of a garden, trenching may be resorted to or a soil 

 insecticide dug in. (4) It is better to avoid growing turnips and 

 cabbages on land adjacent to that which has been attacked the previous 

 year, and in no case should affected land be planted with two successive 

 crops which are liable to attack. 



RoRER (J. B.). Report by the Mycologist on the Inoculation of Locusts 

 with Coccobacillus acridiorum. — Bd. Agric, Trinidad and Tobago, 

 Port-of-Spain, 5th October 1915, 1 p. [Received 9th December 

 1915.] 



A small amount of dried bodies of diseased locusts obtained from 

 the Pasteur Institute, Paris, was macerated in 2 cc. of sterile water. 

 Eight healthy individuals of Schistocerca jparanensis were inoculated 

 each with one drop of the liquid. A single specimen received a double 

 amount of liquid. Seven locusts, serving as controls, were inoculated 

 with water only. A day later the locust receiving a double amount 

 was dead, the other inoculated specimens were sluggish and voided 

 liquid excrement. The controls were active. Inoculation was con- 

 tinued through the third series of locusts, when death ensued in 4| 

 hours. The experiments show that the virulence of the organism can 

 be increased for the Venezuelan locust. Similar results were obtained 

 for the giant Trinidad locust. 



Recent reports from Venezuela state that the locusts there are 

 migrating inland, and therefore an invasion of Trinidad is not antici- 

 pated. It is, however, considered advisable to spray food-plants with 

 cultures of the bacillus when the young hoppers begin to hatch out 

 next year. 



The Control of Ants which take away Onion Seed. — Agric. News, 

 Barbados, xiv, no. 354, 20th November 1915, p. 378. 



Two species of ants are responsible for the destruction of onion seeds 

 in St. Vincent. For the control of these insects, it is recommended 

 that they be burnt off by spreading a layer of dry grass over the beds 

 and setting fire to this. After burning, a few seeds should be placed 



