Digest

Pacific

Planters '

Treating Maize

Against Disease

rO types of maize are generally grown in the Pacific—yellow maize, which is excellent as a poultry feed; and white maize, which finds its way on to dinner tables.

Rust is the most serious disease maize suffers in the tropics, and although Tuxpeno has some resis tance to it, the search is going on for even more resistant varieties.

There is no other form of control.

Maize depends on nitrogen fertilisa tion for success in most areas. It is advisable to apply one cwt. of urea per acre six weeks after planting, and a second application of one cwt. three weeks after that.

If the crop is planted on poor hill soils two cwt. of superphosphate should be applied in addition to the urea. Superphosphate is best applied at seed-sowing time.

Care should be taken when apply ing the urea, for it has a burning effect on plant leaves, particularly if they are wet.

The corn earworm is known in almost all corn-growing areas of the world, and it causes considerable damage to Pacific crops. It feeds on the young seeds at the tip of the cob and allows fungus disease to enter, which results in rot.

The earworm usually attacks the plant two to five days after the silks emerge. Control can be achieved by dusting each silk with 2 per cent.

DDT powder which can best be applied with a small stiff paint brush. This operation is worth while only if the crop is grown for selling as green corn.

Army worms often appear after floods. They can damage maize con siderably, even to the extent of eating off the leaves. They may be controlled by spraying with one ounce of DDT 20 per cent, emulsion per gallon of water.

Blight is quite common and causes large regular yellow streaks on the leaves. This is not serious and can be controlled by treating the seed with mercury dust.

Weed Control With

Chemicals

DESPITE the giant strides made in weed control with chemicals, and the growing popularity of chemicals for farm use, chemical treatment is not the panacea for all weed control problems that some people would lead farmers to believe.

Chemical control should be sup plemented with mechanical control.

The two combined provide excellent results.

An example of this was shown recently when mechanical disturbance of skeleton weed growth followed by spraying increased the effectiveness of the spray.

Research work is currently going on to assess the most effective ways that mechanical control can be combined with chemical control.

Conservative estimates put the cost of weeds to American agriculture at SUSS,OOO million, to Canadian agriculture at S5OO million, and to Australian agriculture at $lOO mil lion.

Its anyone’s guess what the loss is to Islands agriculture, but no doubt it is extremely high.

The Value Of

Selective Herbicides

HERBICIDES, when properly used, alter, inhibit or terminate the growth of weedy plants. Some herbicides kill all plants or at least the plant parts with which they come in contact, but selective herbi cides have been designed to attack one type of weed only and to leave others unaffected by the spray.

The value of selective herbicides is being realised more and more in the tropics.

There are many theories concern ing the reasons why herbicides kill or injure plants, but precise informa tion is difficult to find.

It is known that the slightest dis ruption in enzyme reactions has a marked influence on the growth and development of the plant.

For example, Dalapon, a grass killer, reduces the production of one of the B vitamins, and this vitamin is an essential part of a co-enzyme system.

Substituted urea and tria z i n e herbicides block photo-synthesis, but the actual cause of death probably is not starvation. Certain herbicides block an essential step in the respiration cycle, while others coagulate protein or alter in some way the normal pattern of growth.

The surface of a leaf is covered with a waxy material called a cuticle and this forms something of a barrier

to the entry of herbicides into plants by way of the leaf pores. For this reason surfactants are added to many herbicides to help penetration.

A herbicide applied to leaves and stems may penetrate the waxy covering, enter through the leaf pores, and then move to the food or water conducting tissue, and then to other parts of the plant.

Sometimes the herbicide is absorbed and inactivated by cells in the leaf, and sometimes it may remain on the leaf surface and never enter the plant. The herbicide 2,4-D appears to be absorbed and held more in the cell walls of grass than of broad leaved plants. This factor is probably important in its selectivity.

Absorption of soil-applied herbi cides is through root hairs, and through the cortex cells just behind the root cap. Movement of soil-ap plied herbicides into the plant and to other parts of the plant is with water, and factors which favour rapid growth of plants also favour rapid absorption of herbicides.

Soy Beans For

Pig-Feeding

SOY beans are widely used for pig feeding throughout the world, particularly in the United States.

In Queensland tests recently carried out on soy beans showed that the meal that remains after the extraction of oil—soy bean oil meal—contains 45 to 50 per cent, protein.

The raw beans are not a suitable form of protein, but when cooked or heat-treated they are satisfactory.

The Queensland trials indicated that steam cooking was the best process—the steaming period to be 60 minutes.

After steaming, the beans should be dried by spreading them on shallow trays for a few days. When dried the beans can be hammer milled, as trials have shown that a minor amount of unhammered beans „ goes through the pig undigested.

One commercial company in Brisbane is subjecting soy beans to a heat and pressure treatment to produce a full fat soy bean meal, mainly for their own stockfoods.

Both the boiled beans and full fat meal produce fatter pigs than the soy bean oil meal, due no doubt to the high fat conent of unextracted beans.- - Experiments suggest that the use of soy beans in pig feeding is not dependent on oil extraction. Ex pansion of the soy bean industry in the Solomons, for instance, could provide a valuable protein food ir respective of any demand for soy bean oil.

Control Of Algae

In Ditches

rpHE use of Phygon for the control -!■ of algae in channels and ditches is becoming more popular in the Islands, but as it is not yet known what effects Phygon has on stock, it is unwise to use the chemical for the control of algae in drinking troughs.

The normal approach to the problem of algae in drinking troughs, dams and tanks is the use of either copper sulphate (bluestone) or bleaching powder (chloride of lime).

The recommended rates for use of these chemicals are: • Bluestone: One part per mil lion, i.e., 1 lb of bluestone for each 100,000 gallons or 1 oz per 6,000 of water. The bluestone should be dis solved in warm water before being added to the algae-infested water. • Bleaching powder is used at the rate of 2 oz per 1,000 gallons or 12 lb per 100,000 gallons. This chemical should also be dissolved in a small quantity of hot water before being used.

These strengths are considered to be safe for use by humans or stock, although the bleaching powder may impart a slight taint. It is important that the chemicals be thoroughly mixed into the water to obtain the maximum effect.

Highest Experimental Station

In The South Seas

ANEW agricultural experiment station now being esablished at Tambul, in the Western Highlands of New Guinea, is believed to be the highest such station in the South Seas. The station lies in the Kaugel Valley at a height of 7,350 feet, and is close to Papua’s highest mountain, Mt, Giluwe, which occasionally has snow.

Work at the station will concentrate on pyrethrum but will not be con t fined solely to pyrethrum. It will cover a wide field, and include ex periments to develop suitable frost resistant food crops and to determine the best strains of pasture for high altitude areas.

The initial programme calls for a permanent staff of two agronomists and a field supervisor, with more officers working at the station on an intermittent basis. It is planned to make the station a base for agrono mists working on experiments throughout the Western and Southern NG Highlands, and comprehensive laboratory facilities for visiting specialists will eventually be installed.

In charge at present is Mr. Terry Quinlan, a Department of Agriculture agronomist.