One Thousand Questions in California Agriculture Answered Part 80

Scale on Apricots.

I would like to know how to check the scale on apricot trees.

The most common scale on apricots, the brown apricot scale, is usually held in check by the comys fusca, which is as widely distributed as the scale itself. If it gets beyond the parasite, you should spray in winter with crude oil emulsion. If some scales are punctured or have a black spot on top, the comys fusca is busy and you probably will be safe enough without doing anything.

Fumigating for Black Scale.

I would like to know the best method of eradicating the black scale from my orange trees, whether by spraying or fumigation?

Spraying has been given up as a suitable method for controlling the black scale on citrus trees, and the only recognized method of merit where the scale is bad is by fumigation with hydrocyanic acid gas. You should communicate with your county horticultural commissioner, who, through inspectors, will see that you have a good job done, at the right time and at as moderate price as is compatible with good work. It is impossible to 'eradicate' the black scale, but there is a great difference in the amount that can be killed, and it pays to have a job done as near perfectly as possible. Similar methods of attacking other scale insects on citrus trees are used.

Finding Thrips.

How can the presence of pear thrips be detected in a prune orchard? Will the distillate emulsion-nicotine spray control brown scale as well as thrips?

You can find thrips by shaking a cl.u.s.ter of blossoms, as soon as they open, over a sheet of paper or in the palm of your hand. The thrips are very minute, transparent, somewhat louse-like insects. The spray you mention would probably have little effect on the brown scale which would still be in the egg state and under cover, at the time the early spring spraying for the thrips.

Control of Pear Slug.

I am sending, under separate cover, some samples of cherry tree leaves that have been attacked by a small snail or slug. Kindly let me know what they are, and how to rid the trees of them.

The creatures you speak of are the pear slugs, or the cherry slugs, as they are sometimes known. Although slimy, like the big yellow slug that is a pest in vegetable gardens, it is no relation thereto, but is the larva of an insect. Its olive green color, slimy appearance and the way it eats the surface of the leaves make it about the easiest of all insects to identify. Parasites and predacious insects usually keep it in fair control. Whenever artificial methods of control are needed the slugs can best be destroyed by sprinkling dust of any kind upon them. If you can get a machine for sulphuring a vineyard and use some air slaked lime or other fine dust, it will fix them quickly and inexpensively, though any way of applying dust may be used.

Cutworms and Young Trees.

What method should be used to protect young fruit trees from cutworms?

Hoe around the trees or vines and kill the fat, greasy grubs which you will find near the foliage. Put out a poisoned bait which the worms like better than the foliage, viz. Bran, 10 pounds; white a.r.s.enic, 1/2 pound; mola.s.ses, 1/2 gallon; water, 2 gallons. Mix the a.r.s.enic with the bran dry. Add the mola.s.ses to the water and mix into the bran, making a moist paste. Put a tablespoonful near the base of the tree or vine and lock up the chickens.

Control of Squash Bugs.

We are troubled with pumpkin bugs. Please tell us what to do for them.

When the bugs first make their appearance in the field they can be easily disposed of by hand picking and dropping into a bucket containing about two inches of water with about one-fourth inch of kerosene on top to kill the bugs. The picking should be done in the morning, as the bugs are apt to fly in the warm part of the day and scatter where already picked. Two persons can pick over an acre in one and a half hours, and two pickings are usually sufficient for a season, as after the vines begin to run over the ground pretty well the bugs will not be able to hurt them much. A pair of thin old gloves will help to keep off one's hands some of the perfume from the bugs. The sooner the work starts the fewer bugs to pick. Cleaning up of all old vines in the fall and removing litter in which the mature bugs hide for the winter will permit less eggs to be laid in the spring and there will be fewer bugs to pick as a result.

The Corn Worm.

Last year all my ears of corn were infested with maggot, growing fat thereon. Can you help me scare them away?

You have to do with the so-called corn worm which is very abundant in this State and one of the greatest pests to corn growing. It is the same insect which is known as the boll worm of the cotton in the Southern States. No satisfactory method of controlling this has been found, although a great deal of experimentation has been done. Nearly everything that could be thought of has been tried without very satisfactory results. A late planted corn has sometimes been free, for the insect is not in the laying stage then. If it were not for this insect the canning of corn would be an important industry in this State.

Melon Lice.

I have in about four acres of watermelons, and there seem to be lice and a small gnat or fly, and also some small green bugs and white worms on the under part of the leaves, which seem to be stopping the growth of the vines, making them wilt and die. They seem to be more in patches, although a few on all the vines. Can you please tell me what to do for them?

Melon lice are very hard to catch up with after you have let them get a start. Spraying with oil emulsions, tobacco extracts, soap solutions, etc., will all kill the lice if you get it onto them with a good spray pump and suitable nozzles for reaching the under sides of the leaves.

The gnats you speak of are the winged forms of the lice; the white worms may be eating the lice; the "small green bugs" may be diabroticas. If you had started in lively as soon as you saw the first lice you could have destroyed them in the places where they started. Now your chance lies largely in the natural multiplication of ladybirds and the occurrence of hot winds which will burn up the lice. It is too late probably, to undertake spraying the whole field.

Wire Worms.

Is there any way to destroy or overcome the destructive work of the wireworm, which I find in some spots takes the lion's share of crops, such as beans, potatoes, onions, etc.?

We do not know any easy way with wire worms. Nitrate of soda is believed to kill or repel them, but you have to be careful with it, for too much will either over-stimulate or kill the kill; about 200 pounds per acre, well distributed, is the usual prescription for the good of the plants.

Wire worms can probably be killed with carbon bisulphide, using a tablespoonful poured into holes about a foot deep, three or four feet apart. The vapor would permeate the soil and kill all ground insects, but the acre-cost of such treatment must be measured in its relation to the value of the crop. The most promising policy with wire worms is rotation of crops, starving them out with a grain or gra.s.s crop and not growing such crops as you mention continually on the same land.

Bean Weevil.

How can I keep certain insects from getting into my dry beans? I have finished picking the crop. Every year a little, short, stubby beetle gets in them before spring and makes them unfit for use.