REMEDIAL MEASURES 615 



Palm Beetles. The crown or "cabbage" of coconut and 

 other palms often become attacked by large beetles, more es- 

 pecially the " black beetle," which disfigure the fronds and some- 

 times permanently injure the tree. These beetles may be har- 

 pooned or extracted by a stiff piece of sharp wire (or a long 

 hat-pin) with a barb at the end, the hole being then filled with 

 very fine dry sand. The latter is itself a remedy as well as a 

 preventive, and may be copiously applied to the cavities at the 

 junction of the leaves; it will prevent fresh attacks by more 

 beetles, while it disables any that may already be in their crevices 

 by getting into the joints of their bodies. Red beetles are the 

 most serious, as they attack in enormous numbers, and breed 

 rapidly inside their host; so that if a tree becomes infested with 

 this pest, it must at once be cut down and destroyed. 



Eelworms & Nematodes. A microscopic group of translu- 

 cent animals which often cause considerable injury, or even death, 

 to plants before their presence is detected. They live in the soil, 

 first attacking the roots and rootlets, which in time become knotty, 

 bearing small wart-like excrescences. Plants that are badly 

 affected should be removed and destroyed by fire ; the soil should 

 be opened up and treated with vaporite or a dilute disinfectant; 

 liming the soil, change of plants or rotation of crops are also 

 measures to be advised for the elimination of the pest. 



Wireworms, the larvae of various kinds of beetles, seldom 

 reaching 1 in. in length. They are often a troublesome pest, 

 gnawing the stems and roots of plants just below the surface. 

 An application of vaporite is one of the best remedies. 



Mosquito preventives. The conditions which favour the 

 breeding of the larvae of mosquitoes which are the recognised 

 medium of conveying malaria to human beings are stagnant 

 water, as is frequently found in drains, root-gutterings, discarded 

 tins, broken vessels, bamboo stumps, etc., also damp shade, as 

 under heavy foliage. Plants with water-collecting adaptations, 

 as sheathing leaves or floral receptacles, likewise offer similar 

 facilities for the pest. In addition to guarding against these 

 sources as far as possible, free use should be made of dilute disin- 

 fectants, especially such as leave a film on the surface of the water, 

 as kerosene oil, Jeye's, Cyllin, Phenyl, and Izal disinfectants. 



USEFUL INSECTICIDES. 



Insecticides act in two ways, viz. as a Stomach Poison, 

 when taken internally by the insect with its food; or as a Contact 



