Ontario Teachers' Manuals: Nature Study Part 26

These larvae are easily found during the month of May in little streams of water everywhere throughout the Province. Look for what at first sight appears to be a bit of twig or a cylinder of stone about an inch long moving along the bottom as though carried by currents. Closer observation will result in the discovery that this is a little case composed of grains, of bits of stick, or of sand and tiny sh.e.l.ls, and the head of the occupant may be seen projecting from one end.

Collect some of these larvae in a jar of water and transfer them to the aquarium. Direct the pupils to look for others in the streams, so that they may observe their appearances and movements in their natural environment. If kept in jars, the water must be changed every day, and the top should be covered to prevent the escape of the adults.

~Observe.~--The shape of the various kinds of cases; the materials, and how fastened together (chiefly by silk); the part of the larva that protrudes from the case; the movement, and how caused; the fitness of the case as a protection. Note hardness, colour, and shape as protective features.

The pupils will be fortunate if they observe the sudden rise of the larva to the surface of the water and the almost instantaneous change into the four-winged fly.

INSECTS SUITABLE FOR LESSONS IN FORM II

Walking-stick insect, katydid, cricket, mole-cricket, clothes-moth, giant water-bug, potato beetle, click-beetle, luna moth, and swallow-tail b.u.t.terfly.

CHAPTER IX

FORM III

AUTUMN

GARDEN WORK

The pupils in this Form should be able to do all of the work required of them in the garden without a.s.sistance. They should aim at intensive and thorough cultivation and, in the autumn, when the plants of their gardens ripen, these should be removed and the soil carefully spaded.

They should continue the work of selecting the seed from the best flowers, as indicated in the work for Form II, and should grow some seed from vegetables and perennials seen to be particularly good.

Boys in this Form may also wish to do some gardening for profit. In some cases where there is plenty of s.p.a.ce, this may be carried on in a part of the school garden set aside for that purpose. Usually, however, it will be found most convenient to carry it on in the home garden. Best varieties for local markets should then be grown and attention given to the proper time and manner of marketing or storing for a later market.

Cool, well-ventilated cellars are best for most fruits and vegetables.

TREATMENT OF FUNGI

During the summer and early autumn months attention should be given to the spraying of plants for blight and for injurious insects. The potato is commonly affected by a fungous disease which causes the stalks to blacken and die before the tubers have matured. This disease may be prevented in large measure by the use of a fungicide known as Bordeaux mixture. This may be prepared as follows:

Take one pound of copper sulphate (blue vitriol); make it fine by pounding it in a bag or cloth and then dissolve it in water, using a wooden pail. It dissolves rapidly if put in a little cheese-cloth sack, which is suspended near the top of the pail by putting a stick across the pail and tying the sack of copper sulphate to it. Dilute this solution to five gallons. Take also a pound of unslaked or quick-lime and add a cupful of water to it. When it begins to swell up and get hot, add more water slowly, and, when the action ceases, dilute to five gallons. Mix these two solutions together in a tub or barrel, and churn them up, or stir them together vigorously. They give a deep robin's-egg-blue mixture, which is slightly alkaline and should be used at once. The solutions can be kept separate as stock solutions throughout the summer and then diluted and mixed whenever needed. Care should be observed in not mixing the solutions before each has been diluted to the strength, one pound to five gallons. A piece of blue litmus paper will be convenient to prove that the mixture is alkaline.

If alkaline, as it should be, the paper remains blue when dipped in it.

If the mixture turns the litmus paper red, it must have more lime-water added to make it alkaline. The potato tops should be thoroughly sprayed with this mixture when about ten inches high and then once every two weeks, until they have been treated three or four times. This is to prevent blight and not to kill bugs. If the potato-beetle is troubling the potatoes, add paris-green to the Bordeaux mixture--a teaspoonful to every two gallons. To prove the value of this treatment have a trial plot of potatoes which receive all attention save spraying with Bordeaux mixture. If a heavy rain should follow the spraying, it should be repeated.

Potato-scab may be prevented to a large degree by soaking the tubers before cutting for planting in a solution of formalin (a 40-per cent.

solution of formaldehyde) one-half pint to fifteen gallons of water.

Seed grain is frequently treated this way before sowing, to destroy s.m.u.t spores. A pound of formalin is put in forty gallons of water in a large barrel. A bag full of the grain to be treated is set in the barrel of formalin mixture for about two hours and then taken and dried on a floor that has been previously washed with water containing formalin. A solution of copper sulphate (bluestone), one pound in twenty gallons of water is sometimes used. The grain is left in this solution for twelve hours and then dried for sowing. All bags and utensils should also be disinfected with this formalin solution.

TREATMENT OF INSECTS

In order to poison insects successfully, it is necessary to determine how the insect feeds. If it is a biting insect, that is one that eats the leaf, such as the potato beetle, paris-green should be used.

Paris-green sometimes burns the tender leaves. This may be prevented by adding a tablespoonful of lime to each pail of water used. It may also be used dry with flour or dust.

If the insect feeds by sucking the juices from the leaf, as is the case with plant-lice, then a solution that kills by contact must be used, such as whale-oil soap, one ounce to a quart of water. Tobacco-water is sometimes mixed with the soap solution as follows:

Four pounds of tobacco-waste is steeped in nine gallons of hot water for five hours; this is then strained, and to the tobacco-water one pound of whale-oil soap dissolved in one gallon of hot water is added and mixed thoroughly.

Kerosene emulsion, which is made as follows, is very destructive to plant-lice and scale insects:

Dissolve a quarter of a pound of common laundry soap in half a gallon of rain-water and, while hot, mix with one gallon of coal-oil and churn vigorously for five minutes to get a smooth, creamy mixture. On cooling, it thickens and is diluted before using by adding nine quarts of warm water to one quart of the emulsion. Use smaller quant.i.ties in correct proportions when only a few plants are to be treated.

CABBAGE-WORM

The larvae of the cabbage-b.u.t.terfly sometimes do a great deal of harm by eating the cabbage leaves. It will not do to use paris-green on cabbage, as the leaves are for eating. Instead, use pyrethrum or insect powder, which may be diluted by mixing with cheap flour--one ounce of insect powder to five of flour. Mix thoroughly and leave in a closed tin over night. Dust the mixture on the leaves from a cheese-cloth bag by tapping with a small stick or from a dusting-pan. If used while the dew is on the leaves, it sticks better. Insect powder is not poisonous to man as is paris-green, and so may be used freely on cabbage or other similar plants.

PLANTS

ANNUALS, BIENNIALS, AND PERENNIALS

CLa.s.s-ROOM LESSON

By means of questions based upon the pupils' knowledge of a few common annuals, such as the oat, sweet-pea, and garden aster, develop the following points:

1. These plants are always grown from seeds.

2. These plants produce flowers and ripe seeds during one season's growth.

3. These plants wither and die in the autumn.

Plants having these characteristics are called _annuals_. The teacher explains the meaning of the word and requires the pupils to name a few other annuals.

In a similar way, discuss a few common types of _biennials_, such as turnip, cabbage, hollyhock, and develop the following points:

1. These plants produce no flowers and seeds during the first year of their life.

2. These plants, during the first year, lay up a store of food in roots, leaves, or stems.

3. The food is used in the second year of the plant's life to nourish the flowers and seeds.

A biennial should be grown for two years in the school garden to furnish material for concrete study.

In a similar way discuss a few common types of _perennials_, such as rhubarb, dahlia, apple tree, and develop the following points:

1. These plants may or may not produce seeds during the first year's growth.

2. Some of these plants are herbs, but most of them are trees and shrubs.

3. Food is stored in roots or stems to provide for early spring growth.

4. These plants live on from year to year.

GARDEN STUDIES