206 



lands near to which cotton has been grown and in which it has been 

 stored, although a few may have survived on cotton trees and bushes in 

 sheltered places. This bug has been found in several instances on the 

 cork- wood tree (Ochroma lagopus), which is widely distributed in the 

 island, and it may be necessary to deal with this tree during the coming 

 months. It was not found possible in all cases to enforce the close 

 season for cotton and in many places stalks remained undestroyed 

 until the end of April, while planting began early in May. It is clear 

 that the cotton-stainer takes advantage of any opportunity to survive 

 during the close season. The wisdom of attempting to eradicate 

 the mountain John Bull tree {Sterculia caribaea) is considered 

 doubtful, though it is known to be a food-plant of the stainer ; it is 

 considered that this tree acts as a trap rather than a food for the insect. 

 It is hoped that the fungus, Sporotrichum, globuliferum, which has been 

 discovered among the stainers, will cause heavy mortality. 



Observations made to determine the length of time that adults of 

 D. delauneyi can survive under natural conditions in the absence of 

 regular Malvaceous food-plants, indicate that they can exist without 

 feeding for at least three months by sipping the nectar of flow^ers, 

 honey-dew and water and by remaining in cooL shady places. It is 

 this fact that renders- control so difficult, and indicates that the close 

 season for cotton should be made as prolonged as possible, and that 

 the destruction of native food-plants should be continued systematically. 

 A small trap-crop of cotton might advantageously be planted 

 in April ; to these the surviving insects would be attracted in June, 

 when the cotton starts to flower. Daily collections of the stainers 

 would then have to be made, and the main cotton crop should not be 

 started until June or later. The experience of two seasons has shown 

 that cotton planted in May always attracted stainers to begin breeding 

 in it, while when plantings were later, the insects did not become 

 numerous until the bulk of the cotton had been reaped. In one 

 district a group of Tobago bread-nut trees {Pachira aquatica) were 

 left as a trap for the insects, and on 26th April, when in full fruit, they 

 were invaded by many stainers from the cotton fields. Cotton-seed 

 traps were placed in heaps at the bases of the trees, and the insects, 

 as expected, left the bread-nut for the cotton-seed. These traps were 

 burnt over twice a day from 26th April to 15th June with a kerosene 

 torch and on each occasion thousands of adults were destroyed. In 

 this way the pest in that district was practically exterminated; 



Other pests on the principal crops were not particularly harmful. 

 Edessa meditabimda (pea chink) was fairly prevalent on pigeon peas 

 and ground-nuts in parts of the Windward district. Diatraea saccha- 

 ralis (moth borer of sugar-cane), which had caused much damage in 

 the last three years, declined considerably in numbers, its natural 

 enemies apparently keeping it in check. Calpodes ethlius (arrowroot 

 worm) did little damage, and no outbreak of Alabama argillacea was 

 recorded. 



"Lucerne Flea." — Jl. Dept. Agric. S. Australia, Adelaide, xxiii, no. 6, 

 January 1920, p. 502. 



The lucerne flea (Smynthurus viridis), an insect of the order CoUem- 

 bola, is troublesome in some years in South Australia. It attacks 



