411 



NowELL (W.). The Red Ring Disease of Coconut Palms. Infection 

 Experiments. — West Indian Bull., Barbados, xviii, no. 1-2, 

 1920, pp. 73-7G. [Received 22ud July 1920.] 



In a paper previously noticed [R.A.E., A, viii, 66] artificial infection 

 experiments with the red ring disease of coconut palms were recorded, 

 and a fuller account of them is given here. Pieces of tissue infested 

 with A])helenchus cocophilus, Cobb, the Nematode causing red ring 

 disease, were inoculated into the stems or petioles, or dropped into the 

 axils of healthy trees. Of eight trees thus treated, six were found 

 infested after sixty to seventy-four days. The two failures were trees 

 in which infection was attempted in a basal leaf. During the period 

 of the experiments, February- August 1919, one tree among the forty- 

 two remaining trees in the plot was infected naturally. The next case 

 of natural infection occurred in November of the same year. 



The rapidity of infestation shown in the experiments renders 

 untenable the hypothesis that infection takes place at an early age 

 without its effects becoming manifest until the tree matures. 



The results support the idea that infection occurs in the leaf-bases, 

 and more recent observations in Trinidad suggest that this may fre- 

 quently take place by way of the small cracks that develop in the fold 

 made on the outside of the leaf-base by the bending outwards of the 

 leaf as it matures. In many leaves examined there was a narrow 

 streak of infested tissue connecting this point with well-developed 

 infestations in the softer tissue further along the petiole. 



HuTSON (J. C). The Paddy Bug {Leptocorisa varicornis, F.). — 

 Trop. Agriculturist, Peradeniya, liv, no. 6, June 1920, pp. 363- 

 366, 1 fig. 



Leptocorisa varicornis, F., is one of the chief pests of rice in Ceylon 

 [R.A.E., A, vii, 349]. The " maha " [chief] crop, which reaches its 

 critical stage in February and March, is usually more seriously damaged 

 than the later crops which flower in July and August. The remedial 

 measures advocated include the use of the bag net, which is illustrated. 



Jarvis (E.). Notes on a little known Leaf-eating and Stem-boring 

 Beetle. — Queensland Agric. Jl., Brisbane, xiii, no. 6, June 1920, 

 pp. 274-276, 1 plate. 

 The Chrysomelid, Rhyjmrida morosa, Jac, of which the larva and 

 pupa are here described, has been recorded as seriously injuring 

 sugar-cane in Queensland. The chief damage is caused by the larva. 

 The beetles feed on the leaves of sugar-cane and of their native food- 

 plant " bladygrass " {Imperata arundinacea). They may also be 

 found on young twigs of Ficus opposita. The larvae pupate nine days 

 after entering the soil and the adults appear nine days later. The 

 adult beetles are preyed upon by a Reduwid bug and an 

 undetermined Tachinid fly has been bred from the larva. 



Division of Entomology. — Jl. Dept. Agric, Pretoria, i, no. 2, May 1920, 

 pp. 168-171, 1 fig. 

 Icerya purcJiasi continues to be a pest of Citrus and roses in parts of 

 the Cape Province, but its ravages are greatly checked by the 

 Coccinellid, Novius cardinalis. 



