Digest

Pacific

Planters’

\Aany Tropical Soils

)Eficient In Phosphorus

A SURPRISINGLY large number of tropical areas are deficient in •hosphorus, the cause being high ainfalls, the continual washes from vhich leach valuable minerals from he soil.

It has been found that generally attle in high rainfall areas do need supplementary intake of phosphorus nd this applies particularly to milk ng cows, which have high phosphorus equirements because of the amount if the mineral in milk.

The only symptom in mild phos horus deficiency may be a slight rop in milk production, which sually passes unnoticed.

With a more marked deficiency iere is a depraved appetite. Affected nimals chew bones and other □reign material. In still more dvanced cases of phosphorus eficiency, bones become fragile and ractures occur readily. In addition iere is lameness, through erosion f the joint surfaces of bones.

There are many ways of supplying hosphorus to cattle to rectify a eficiency, and the most common ne is by means of licks which very ften can be mixed by the farmer imself.

A mixture of equal parts of coarse alt and either bonemeal or ground □ck phosphate makes a good phos horus supplement. It has the added dvantage of being cheap and easy to repare.

Owl Leucosis

CHE disease which causes the most deaths in poultry after the licken stage in tropical areas is ;ucosis.

While there are a number of ifferent forms of leucosis the most □mmon are neural leucosis, in which srtain nerves are involved resulting i paralysis, and visceral leucosis, i which internal organs are affected.

The first sign of neural leucosis is sually a partial paralysis of one g. Later the paralysis becomes more larked, with both legs being affected ) that affected birds can’t walk and

tend to flounder with the support of their wings. Later the wings also may become paralysed.

The paralysis that accompanies the neural form of the disease should not be confused with limb weakness that may be caused by malnutrition, vitamin deficiency, worm infestation or other diseases.

In the visceral form of leucosis, there is usually loss of appetite, diarrhoea and a wasting away.

Older birds may carry the disease and be sources of infection to young chickens, so rearing of chickens well away from older birds is recom mended. Unfortunately, this is not always effective, as cases have been known in birds reared on wire floors from the chicken stage.

A great deal more research needs to be done before leucosis can be controlled. Recent experiments in the United States suggest that birds well fed at the time of infection are more susceptible to leucosis than under nourished birds. At the Veterinary Research Station, Glenfield, Victoria, an important observation has been that extra riboflavin in the diet for 14 days may be of some value in relieving the condition during an outbreak.

Science—Plus Efficiency

Help Control Weeds

THE control of weeds—of undesir able species of plants—is some thing that man has had to contend with since the beginning of agricul ture. No matter which of the many methods are used it has always been a long and laborious business.

Now the scientists and chemists have come to the farmer’s assistance with chemicals which enable him to considerably reduce his labours, which in turn eventually reduce the overall cost of production.

Selective weedicides have been formulated which will kill broad leafed plants and leave narrow leafed ones growing, and vice versa.

Herbicides have been devised which will deal effectively with water grown weeds and there are other materials available which can be used against weeds in orchards without any apparent ill-effect to established crops.

Where weed control with chemicals is a comparatively new innovation there is a tendency to be trapped in the pitfall of thinking chemical weed control is an end in itself. It can be, but very seldom.

After weeding with chemicals a wise farmer will endeavour to follow up the spraying with good farming practices, such as pasture improve

nent and rotation of crops, to prevent e-infestation. Spraying is no sub titute for sound farming practices.

In most cases it is necessary to nsure that when weeds are killed iseful plants are encouraged to re dace them. Adequate fertilisation nd heavy grazing are important in aaintaining weed-free pastures.

In some cases, well managed and nproved pastures can be sufficient reed control in themselves, although lis is more the case in temperate limates rather than the tropics, where igh rainfalls and persistent winds re conducive to the spread and rowth of weeds.

When you spray, remember that eeds generally are more susceptible ) chemical control when in the Dung, actively growing stage, before owering begins.

Evin For Control Of

Eaf Hopper

HHE insecticide Sevin has shown L itself a top-flight chemical for af hopper control in the Solomons, fact of primary interest to all rice rowers in the Pacific, as leaf hoppers ave shown themselves the rice -ewers’ main pest.

The promise that Sevin could work ?ainst leaf hoppers with satisfactory :sults was established at the Inter ational Rice Research Institute in ic Philippines, after basic research ork on the subject had been done : Japan.

One unique use for Sevin has been »und with a granular formulation )plied right in the rice paddy water •r the leaf hopper control. Further welopment of this technique has ken place recently by combining win with BHC in granular form for iddy application. A happy result of is insecticide combination is the mtrol of both leaf hoppers and rice em borers.

Tests also have shown good Sevin :rformance on mangoes in the lilippines, and on cocoa in Ghana id Nigeria for control of cocoa ipsid, all of which augurs well for milar performances in the Pacific.

Since it was first introduced as a meral purpose insecticide in 1956, ;w markets have opened up for win at a surprising rate.

One main reason for Sevin’s ipularity is that early tests showed to be less hazardous than most •mmon insecticides on the com ercial market. Combined with this •mparative safety, Sevin has shown elf effective against a number of sect species which had grown sistant to earlier insecticides.

Supporting the concept that Sevin one of the safer insecticides, a

new label was granted by US authorities recently for the use of Sevin by pest control operators to control household insect pests. These pests include cockroaches, ants, brown dog ticks, earwigs and mil lipedes in and around homes, apart ments, hotels, restaurants and other similar structures.

Unfortunately, while its action is effective against such a variety of pest, notable exceptions are the house fly and spider mite.

Sevin has been found to be the practical answer as an insecticide to

be used on crops grown as livestock feeds, or adjacent to dairy or beef cattle. The insecticide does not carry through into milk or meat, thus overcoming one of the larger handi caps of many of the chlorinated hydrocarbon insecticides.

When used in direct application to poultry, no changes have been noted in egg production, hatchability, chick survival or growth. Sevin’s effectiveness against ectoparasites of poultry has proved important to poultrymen everywhere, particulary in the Pacific where it is widespread.