One Thousand Questions in California Agriculture Answered Part 79

Control of Gra.s.shoppers.

This county is having trouble with the gra.s.shoppers as are other counties. Would you kindly inform me what I could do to exterminate them on my young orchard?

The best thing for gra.s.shoppers is to fix up a lot of poison. This is made in the proportion of 40 pounds of bran, 2 pounds of mola.s.ses and 5 of a.r.s.enic, mixed together as a mash. They will take this wherever they find it, even when nice green leaves are close by, but it has to be kept moist. Gra.s.shoppers can also be reduced by driving a "hopper doser" over ground where they are. This is made somewhat like a Fresno sc.r.a.per, but is much longer and the bottom is covered with crude oil. When disturbed the hoppers jump up and fall into the oil. Besides the poison, you should also protect the trunk of the tree to prevent the hoppers from climbing up it. This can be done by applying tree tanglefoot, or putting on one of the tree guards that prevent climbing insects from pa.s.sing up to the leaves. The combination of poison and tree guards will give you about all the protection you need.

Sunburn and Borers.

Please state the best remedy for keeping the borer out of young fruit trees.

Sunburn can be prevented in many ways. The manufactured tree-protectors are good if they are light colored and are kept in place so that the sun does not scald above or below them. Wrapping spirally with narrow strips of burlap, torn from old grain sacks, from the base to the forking of the branches, is also good. A very effective and widely used method is to apply a good durable whitewash which may be made of 30 pounds of lime, 4 pounds of tallow and 5 pounds of salt, adding the salt to the water used in slaking the lime, stirring in the tallow while the slaking is in progress and hot, and then adding water to thin the wash so that it will work well with pump or brush.

Gumming of Prune Trees.

I write to ask for information concerning my prune trees. They are from two to six years old and the gum is exuding from them. As I notice the branches dying I cut them out, but this doesn't seem to save the tree. I would appreciate any information you can give me.

This is a pretty hard matter to diagnose from a distance. There is a good probability that the trouble is caused by sunburn, a point you could determine on inspection. Whitewash would be a protection against this and more or less of a cure also. Furthermore, borers may be the cause, which can be determined by examining the points where the gum exudes, seeing if any wood grains are present. These borers should be dug out and whitewash applied, which latter also protects against this trouble. Lastly, your ground may be drying out, which also you can determine and remedy.

Borers in Olive Twigs.

There are quite a number of olive trees in this locality that have something wrong with them. They make a growth of five or six inches and the center twig dies back, then it sprouts out at the sides and makes another growth in the same way. This makes a thick bush instead of the tree coming up as it should.

The dying back is caused by a beetle which bores into the twigs. The twigs above the point where the beetle enters dies and then, of course, buds come out from healthy wood below. No treatment has been devised against it, though its breeding ground is limited if all dead wood and brush and litter is cleaned up and twigs are cut off below the point of injury whenever the work of the insect is seen.

Raspberry Cane Borer.

Can you tell me what to do for my Loganberries and raspberries? A small worm got into them in the new growth of wood lost summer, right in the tips of the new growth of wood, and then worked down through the pith of the wood, and as fast as they worked down the can wilted.

This is the raspberry horn-tail, or the cane-borer. The adults are wasp-like insects about a half-inch long and very active. They come out of the canes in spring and the females soon lay eggs in the tender tips of the young shoots. These eggs soon hatch and the larvae eat their way up toward the tip, which causes it to wither and die. It is this injury that causes much notice. As the tip dies, the larvae turn and go down into the canes, as in the sample sent, also injuring them greatly, though possibly not killing them for some time. The only way to attack them is to pinch the spots where the eggs were laid; then those that escape and cause the tips to wilt should be destroyed by cutting off the tips below the point of injury or cutting off the canes when they show damage. Likewise, the insects work on the wild rose, and cutting all those out around a place will prevent enough adults from developing to permit little damage to be done, always provided the berries are well looked after.

Control of Red Spider.

Can you give directions for the prevention of injury by the red spider to almond and other trees in the Sacramento volley?

The red spider on almond and prune trees is usually controlled by the thorough application of dry sulphur to the foliage. On almonds the first sulphuring should be done as soon as the leaves appear in March. A second application is advised from the 1st to the 10th of May. A third application should be made from the 1st to the 10th of June. Prune trees should be treated as soon as the spider appears. In the Sacramento valley this usually occurs about the first week of July. Full-grown trees require about a pound of sulphur which should be thoroughly distributed throughout the foliage. The old method of throwing a handful of sulphur in the branches of the tree or on the ground under the tree is valueless. The use of a blower is economical in large orchards, but a can with perforated bottom is frequently used on young trees or small orchards with good results. In normal seasons the spider is easily, controlled by dry sulphuring. When the pest does not yield to this treatment, a spray is recommended.

Liquid Spray for Red Spider.

Is there any liquid spray I can use in my spraying that will kill the red spider without injuring the foliage of the almond?

A liquid spray for red spider is made by taking sulphur 30 pounds; lime (reduced to milk form by water), 15 pounds; water, 200 gallons; or use commercial lime-sulphur, 4 or 5 gallons to 200 gallons of water. These sprays can be applied without injuring the foliage. They are more expensive in labor cost than dry sulphuring, but are more effective.

Apple-Leaf Aphis.

I am sending herewith a small piece from one of my young apple trees. If you can, will you kindly tell me what the insects are an it, and what I had better do for them?

The apple twig which you send is infested with the eggs of the leaf aphis or leaf louse. These eggs are very difficult to kill. A good thorough spraying with lime-sulphur might, however, get rid of many of them and would be good for the trees otherwise - diluting according to condition of tree growth. The chief campaign against the leaf aphis, however, must be made early in the growing season, just as these pests are beginning to hatch out and to acc.u.mulate under the leaves of the new growth. They should then be attacked with properly made kerosene emulsion or tobacco extract with a nozzle suited to land the spray on the under side of the leaves. Unless these pests are attacked early in the season and repeated if necessary, your apples on bearing trees will be ruined so far as they attack them, being small, misshaped and worthless. On young trees the destruction of the foliage is fatal to good growth.

Woolly Aphis.

Will you kindly inform me what you consider the best treatment for apple trees affected by woolly aphis?

The best way to kill the woolly aphis on the roots is to remove the earth from around the tree to a distance of one or two feet, according to the size of the tree, digging away a few inches of the surface soil, Then soak the soil around the tree with kerosene emulsion, properly made, of 15 per cent strength, and replace the earth. Be sure you get a good emulsion, for free oil is dangerous. For the insects above ground on the twigs, a good spraying while the tree is out of leaf will kill many, but some will survive for summer spraying, and for this a tobacco spray may be most convenient.

Blister Mite on Walnuts.

I am sending you some walnut leaves with some swellings an them. They are very plentiful on some trees here. Is the trouble serious and will it spread?

This is merely Erinose, or Blister Mite, which is a very common trouble on walnuts, but does not do enough damage to call for methods of control. These swellings are caused by numerous, very small insects which live within the blisters on the under side of the leaf amongst a felt-like, heavy growth which develops there. While this effect is very common, it produces no appreciable injury and needs no treatment for its control.