Pacific Planters'

Digest

Use Of Chemicals

In Land Clearing

THE use of chemicals for killing trees and scrub has become an accepted practice in land clearing.

Suckering and basal re-growth have been greatly reduced compared with that occurring after manual or mechanical clearing methods.

Until now, however, chemicals have been either costly and not completely effective, or they have been poisonous and dangerous to both man and animals.

A new herbicide, Tordon, which is also a growth regulator, has had outstanding success as a tree-killing chemical under tropical conditions, and has proven itself not only for its economy and efficiency, but also for its complete safety to man and animals.

Several methods of applying Tordon for tree-killing have been developed—the method chosen being largely dependent on the size of the tree and its accessibility.

For killing standing timber over 3 in. in diameter, the fastest and cheapest methods are the “partial frill method” or one of the “tree injection techniques”. These are also effective on seedlings.

Where timber is being felled and suckering has to be prevented, the

“cut stump method” is advised. If trees have suckered badly following ringing, or seedling growth, and scrub has to be killed, the use of high volume or mistblower “overall foliage sprays” is advised.

The “partial frill method” and “tree injection techniques” of tree killing are based on the principle of placing the chemical directly into the sap stream of the plant. This is done by making a cut into the sap-wood of the tree and placing into the cut a measured quantity of chemical.

Methods Partial Frill Method: Use an axe or any other suitable cutting equip ment to make a series of downward cuts through the bark into the sap wood. This may be done at any convenient height. Space the cuts evenly every 6-8 inches around the circumference, and into each cut apply a 1 cc. measure of a solution containing one gallon of chemical plus four gallons of water (1 in 5).

Care must be taken to apply this to the cut wood surface and not to waste it on the bark. An automatic vaccinator or similar equipment which can be accurately calibrated to deliver 1 cc. doses should be used.

Tree Injection Techniques: A

number of specially-designed tree injectors are manufactured, and, although relatively expensive, they can be much faster than the “partial frill method”. These tree injectors are designed to make a suitable cut into the tree and to deliver a measured dose into this cut. NOTE: Injection into trees which bleed profusely is unlikely to be effective.

Complete Frill Method: Where preferred, a complete frill ring can be made by a series of downward axe strokes through the bark into the wood, at the same time turning over the wood to form a ring around the tree. This frill should then be thoroughly wet by spraying or swabbing with a solution of one gallon of chemical in 50 gallons of water. This frill may be made at any convenient height.

Cut Stump Method: Smaller trees can be cut down by axe or chain saw, and the cut surface thoroughly wet by spraying or painting with a

solution of one gallon of chemical in 50 gallons of water. This should be done as soon as possible after the trees are cut. Chain saws often leave a coating of oil on the cut surface and the addition of a non ionic wetting agent to the solution is recommended.

Overall Foliage Spray: This method of application is useful where regrowth, regeneration or suckers are to be controlled. Foliage should be sprayed when 2-4 feet high and making active growth.

Spraying after this stage is also effective though more spray will be used. Thorough spraying is essential.

With high volume and medium volume sprayers, spray with a mixture of one gallon of chemical in 100 gallons of water. Wet foliage to the point of run-off.

With mistblowers, mist thoroughly with a mixture containing eight fluid ounces of chemical per gallon of water. Misting should continue until moisture is just visible on the leaves.

Overall foliage spraying should aim at applying no less than one gallon of Tordon per acre of dense growth. WARNING: Mistblowers and, to a smaller extent, high volume sprayers must be closely controlled to prevent spray mist drifting on to nearby susceptible crops. Under windy conditions spray drift can be blown for miles.

It is worth recording that 1 gal. of Tordon should be sufficient for making 22,370 injections at recom mended rates. The area of timber which can be treated depends on the number of trees per acre and their size.

Iron Deficiency

In Pigs

PIGS are the most susceptible of all domestic animals to iron deficiency, and nowhere is that deficiency more apparent than in tropical regions.

In all parts of the world piglets are born with only a limited store of iron, and unless an external source of iron is made available, they can become severely anaemic during the second to fourth weeks of life.

Iron deficiency is a major factor in piglet farming, and can cause a big reduction in pig-breeding profits.

Anaemia leads to stunting, lowered resistance to disease and, in severe cases, to death.

A new-born piglet, weighing 3 lb, has about 50 mg of iron in its body.

Piglets grow rapidly, increasing in weight about four times in the first three weeks and 12 times by the end of eight weeks.

To prevent anaemia, a piglet needs at least 7 mg of iron per day and

preferably 10 mg. Sow’s milk con tains only about 1 mg per day, hence some other way must be found to give iron.

Old methods of trying to give iron to piglets include putting a clod of earth in their pen, feeding oral iron tablets, or smearing teeth or tongue with a paste containing iron.

None of these methods was entirely effective and so immediate success is predicted for a new iron dextran product which is injected.

A single 2 cc. dose of the iron dextran, injected into the piglet’s ham muscle at three days old, gives each pig 200 mg. of iron. This dose is completely and quickly absorbed.

One injection, costing only a few

shillings gives three weeks’ iron requirements—enough for complete protection against iron deficiency until supplementary feeding takes over.

New Weedicide

For The Tropics

ANEW weedicide, now introduced into the tropics, will—when mixed into the soil before planting a crop—control weeds for some months as they germinate from seed.

The weedicide is an emulsified concentrate containing the active in gredient, trifluralin.

When mixed into the soil, this pre emergent weedicide allows the seeds

of susceptible weeds to germinate and first leaves and roots to form.

But it prevents the roots from developing any further. Hence, the seedling dies.

The new weedicide has a marked advantage over earlier weedicides in that it gives positive weed control under any soil and climatic con ditions.

It also has another advantage in that it will not leach away with heavy rains, and it stays put under overhead irrigation and furrow watering.

The correct amount of the weedicide should be used for the soil type. Under-application can result in poor weed control. Over application may cause damage to crops.

The weedicide does not control established weeds and, in most cases, it does not harm crops which are transplanted or already established.

For instance, it can be applied or incorporated prior to the planting out of vines, citrus and other orchard trees.

In general, it can be said that any plant with an established root system will be tolerant to the new chemical.

Specialists are not so certain about crops growing from cuttings or vege tative pieces.

For instance, although the weedicide is used for weed control in potatoes, it is not placed around a potato set (cutting). If the potato set is placed in treated soil, its growth will be retarded.

Some other crops grown from cuttings or vegetative pieces are sugar cane and pineapples. As yet it is not known how these crops react to the weedicide.

While the new weedicide will control quite a wide range of weeds with excellent results, it will not control all weed species, nor, in fact, will any other selective weedicide, • Authorities at the Natural History Museum, Vienna, have named a previously unknown species of praying mantis after a New Guinea man, Dr. J. Szent Ivany, who dis covered the insect a few years ago.

Dr. Szent Ivany is senior entomologist with the P-NG Department of Agri culture.

The new species has been named Hierodula szentivanyi.

During 12 years with the Depart ment of Agriculture, Dr. Szent Ivany has had more than 20 species of insects named after him. A new genus of beetle he discovered also bore his name.