Learn about how to prevent and control pests in garden!
How to Prevent Pests in Garden?
Give Your Garden a Good Start:
One of the most common methods by which disease-producing bacteria and fungi are introduced into gardens is by way of seeds or planting stock. The disease organisms may be on or in the seeds or plants and only require to be placed in a favorable environment to begin their destructive activities. Once in the soil, these disease organisms may live from year to year, taking their annual toll of your crops. The obvious means of avoiding these and other troubles and obtaining good stands of disease-free crops are those that every gardener can practice.
1. Buy healthy or certified seeds or planting stock from a reputable seed company or dealer. Bargains may gain you nothing but poor stands and new diseases.
2. Purchase disease-resistant varieties whenever possible or practical.
3. Disinfect seed that may carry disease organisms.
4. Protect seed with chemicals from decay organisms that live in die soil.
5. Sterilize soil in which seeds are to be planted.
6. Rotate the position of the different plant families in your garden from year to year.
Why Treat Seed?
Irregular stands of vegetables may be due to weak or diseased seed or to the presence of soil fungi causing seed rots and damping-off. Damping-off is the name given the symptoms and the disease characterized by the rapid rotting of the bases of seedlings, and their consequent falling over and death. Several species of fungi may be responsible for this trouble, but the treatment is the same. Seed decay often occurs when planting is followed by cold wet weather; while damping-off occurs mostly under warm damp conditions such as are found when seed flats are kept in houses, greenhouses, or cold frames.
Some seeds are more susceptible to rots and damping-off than others. Peas, beans, lima beans, spinach, cucumbers, melons, squash, beets, corn, and tomatoes are often affected by seed rots or damping-off, while other vegetables are attacked to a lesser extent. You may get by without treating seeds, but your good fortune will not hold but indefinitely, and actual crop increases are shown from treated seeds over untreated ones. Some seed companies may treat some of their seed before putting them on sale and save you the trouble.
Protecting and Disinfecting Seed:
There are numerous chemicals on the market under various trade names that have value in protecting, and, to a lesser extent, disinfecting seed. Some are more effective for some seeds than others. To simplify matters, only three effective chemicals will be considered. They are “Semesan,” “Spergon,” and “Arasan.” All are in powder form and are applied to the seed coats so that they form a continuous shield against fungus invasion. This means that every bit of the seed surface must be covered with a light film for the best protection.
Directions for treating are given on the containers, but usually not for such small amounts as ten-cent seed packages. In that case, a pinch of the chemical placed in the seed package and shaken vigorously will be enough to give the seeds a fine, even coating of the powder. For larger quantities of seeds, a glass jar with a cover is excellent for shaking and coating them with the chemical protectant. Be careful not to get too heavy a coating of dust on the seeds, as this may result in delayed germination or injury.
“Arasan” is probably the best general protectant, and may be used on all vegetable seeds. “Semesan” is recommended for the cole crops, such as cabbage, broccoli, cauliflower, etc.; for cucurbits, such as cucumbers, squashes, melons, etc.; for sweet corn; for celery; for beets; and for spinach. “Spergon” is effective on smooth-coated seeds such as cucurbits, sweet corn, peas, and beans, including lima beans.
Two- or three-year-old celery seed is blight free, and, in addition, should be protected with “Semesan” or “Arasan” when planted.
Potato tubers to be used for seed require a special treatment for disinfection and protection. Dip and wet the potatoes thoroughly in a mixture made up by putting 2 ounces of yellow oxide of mercury in suspension in 4 gallons of water. Then drain and dry the tubers before cutting them into seed pieces. Use certified seed when obtainable.
The seeds of cole crops and the tomato family may be disinfected by dipping in a corrosive sublimate solution made by dissolving 1 tablet (7 ½ grains) of corrosive sublimate in 1 pint of water (1 = 1,000 dilution). The seeds of cole crops are soaked for fifteen minutes; seeds of eggplant, ten minutes; seeds of pepper, two minutes; and seeds of tomato in 1 = 2,000 dilution, five minutes. After treatment the seeds should be washed for fifteen minutes and either dried or planted. Wood or glassware containers should be used, as the chemical corrodes metals. This material is very poisonous when taken internally and must be handled and disposed of with care.
Sterilizing Soil:
It is often necessary to sterilize garden soils infected with persistent disease organisms, or to sterilize small quantities of soil to be used in flats or seed beds to prevent damping-off. Several methods may be used.
i. Heat Sterilization:
A small quantity of soil may be easily sterilized by placing it in a flat container and baking it in the oven for as long as it takes to bake a medium-sized potato.
ii. Formaldehyde Soil and Seed Treatment:
This treatment, recommended by the New York State College of Agriculture, disinfects seeds, soil, and flat in a single operation. Sprinkle over each bushel of soil a formaldehyde solution made by mixing 2 ½ tablespoonfuls of commercial 40% formaldehyde with about ¾ cup of water. Mix the soil up thoroughly and place it in flats. Wait for about a day before sowing seeds. After the seeds are sown, water the soil thoroughly.
iii. Formaldehyde Soil Disinfection:
Dilute commercial formaldehyde at the rate of 1 part to 50 parts of water, or 5 tablespoonfuls to 1 gallon of water, and, with the aid of a sprinkling can, soak the garden soil thoroughly after it has been prepared for planting. From ½ to 1 ½ gallons of solution per square foot are necessary for this treatment, depending on the dryness of the soil. Wait about ten to fifteen days before planting seed or setting out plants. Formaldehyde is not effective against soil-inhabiting insects.
iv. Chloropicrin Soil Treatment:
Sometimes stubborn soil- borne diseases defy the above methods used for their eradication; then chloropicrin, a liquid which evaporates as a gas (sold under the trade name “Larvacide”) may be used with great effectiveness. It is safe to use outdoors, as even in sublethal concentrations it is so irritating to your nose and eyes that you cannot remain in its vicinity. This chemical is a most complete soil sterilizer, killing all soil organisms; even most weed seeds.
The soil is prepared for planting; holes about 4 to 5 inches deep staggered 12 inches apart are then made; and ½ teaspoonful of the liquid placed in each hole, which is promptly covered over. Applicators may be available for injecting this material into the soil. After the treatment is made, the soil surface should be wetted to a depth of about ½ inch and covered over with wet paper or burlap for two days. Wait ten days after treatment is completed before planting seed.
Soils cannot be effectively sterilized with growing plants in them without harming the plants.
What are the Disease-Resistant Varieties?
Many varieties of vegetables have recently been bred that are resistant to certain diseases. Resistance rarely means complete immunity, however. Under favorable conditions, a disease may appear in a resistant crop, but it usually is never as disastrous as in susceptible varieties. When certain diseases for which there are resistant varieties are prevalent in your neighborhood and these varieties are adapted to that region, it is courting disaster not to utilize them.
In addition, it pays to obtain certified seed, which signifies that the crops from which seeds are to be collected have been closely inspected by government or state inspectors and found to be disease free, or nearly so. Look for disease-resistant or certified varieties when ordering or buying your seed supply.
How to Control Pests in Garden?
Spraying and dusting are the most commonly used practices, but by no means the only ones that can be employed against plant pests. The basic requirement for equipment used in spraying and dusting is to produce a thorough coverage of the plant with a minimum of (1) time, (2) labor, and (3) material.
Many ambitious attempt to control pests has ended in discouraging failure mainly because the equipment was faulty or inadequate. It would be foolish to attempt to paint a house with an artist’s brush; yet many a person armed with a small atomizer thinks he is doing a good job of spraying a tree in ten minutes or even half an hour.
To Spray or Dust?
Many a beginner is puzzled by the choice between spraying or dusting his plants to control pests. Either or both can be done; or the equipment that you have on hand may settle that problem. As most of the chemicals used in pest control can be obtained for use either in spray or dust forms, the choice may depend on the advantages and disadvantages of each method.
Dusting is recommended over spraying for vegetable gardens and bush fruits because:
(1) You can dust much more rapidly than you can spray;
(2) Dusting equipment is lighter to handle and simpler to operate;
(3) It is better adapted to low-growing crops;
(4) It gives a greater range of penetration to all parts of the plant;
(5) There is less danger of injury to plants; and, finally,
(6) Higher cost of dusts is offset by saving time and labor.
Spraying is recommended over dusting for fruit trees because:
(1) Dusting is not effective against the dormant stages of the pests on the trees;
(2) Dusting is not as effective as spraying for certain fruit pests;
(3) Dusting of trees for gardens cannot be done in windy weather or on dry foliage;
(4) There is greater peril of irritation from poisonous dusts and from drifting dust settling where it may be harmful to plants or animals.
Choice of Spraying Equipment:
Sprayers and dusters may be purchased at hardware stores, feed and fertilizer stores, or from horticultural supply stores. Select the equipment best suited for your garden.
The atomizing types of hand sprayer are not recommended for gardens, even small gardens, as it is difficult to get good coverage with them and impossible to cover the undersides of the foliage of low-growing plants. Small sprayer is handy for a few plants because the flexible hose allows spraying in any direction. It is operated by flexing your hand while spraying, but this operation becomes tiring if continued for any length of time.
Bucket pumps are inexpensive and can be used effectively for vegetables or small fruit trees, when provided with about 10 feet of hose and a suitable spray gun. The spray is continuous, but two people are required to operate the equipment efficiently.
Knapsack sprayers are of two types. The compressed- air type is the most popular, holding from 2 to 3 gallons of spray. Air within the tank is compressed until a pressure of about 50 pounds per square inch is obtained. When the discharge valve on the spray gun is opened, the air pressure forces the liquid out of the nozzle.
For good pressure, never fill this type of sprayer more than about two-thirds full of spray. This sprayer can be handled effectively on vegetables and dwarf trees by one person, but has the disadvantages of a gradual decreasing spray pressure and lack of an agitator to keep suspended materials from settling in the tank. Frequent shaking of the tank is necessary.
The other type of knapsack sprayer overcomes these disadvantages but is much more tiring to operate. Women would find it too difficult to operate, as well as too heavy to carry for any length of time.
The wheelbarrow sprayer is a very handy and not too expensive type which combines the effectiveness of the bucket pump for vegetables and fruit trees with ease of transportation. An expensive motor-driven type is very efficient and eliminates the services of an extra person.
The barrel sprayer, equipped with an enlarged type of bucket pump, is inexpensive. Mounted on a cart of some type and equipped with 25 feet of hose, it can be used effectively in a small orchard. Note that an agitator is desirable in all sprayers to keep the spray materials evenly distributed throughout the water.
What to Look for in a Spray Gun:
A sprayer can be no more efficient and effective than its spray gun. The most satisfactory type of spray gun for small sprayers is equipped with a trigger release, a fairly long barrel, and an adjustable nozzle. The trigger release makes it possible to operate the spray gun with one hand; the long barrel makes it easy to reach low-growing plants or distant parts of trees; and the adjustable nozzle is essential for spraying the undersides of low-growing plants without back-breaking effort. If the nozzle is adjusted so that it points nearly at right angles to the barrel of the spray gun, the top and undersides of foliage can be sprayed by a simple twist of the wrist.
Adjusting the Spray to the Plant:
The nozzle has an important bearing on the effectiveness of the whole spraying operation, yet very few people know that they can adjust a standard nozzle to produce almost any type of desired spray. Know the parts of a nozzle, for you may have to take it apart innumerable times for cleaning and adjusting. The only part that usually gets worn out is the hole in the disk. When the orifice becomes enlarged, the spray comes out in an uneven cone.
This may be corrected for a time by turning the nozzle disk over so that the worn- out edge of the orifice faces inward. The openings in disks are designated by a number on the disk—as a rule the smaller the number, the smaller the hole.
The vortex or whirl plate has 2 to 4 holes in it at an angle. This causes the spray to be thrown into a spin and break up so that it leaves the nozzle in tiny droplets in the form of a hollow cone. If a solid-cone spray is desired, a hole the size of the nozzle orifice must be bored straight through the center of the vortex plate opposite the disk opening. For close-up work, less than 2 feet from the nozzle, a solid-cone spray gives more even coverage.
A solid-cone spray also carries much farther than a wide-angle cone spray. Sprays should be fine but not too misty, as a coarser spray is more penetrating and gives better coverage. Irregular disk orifices cause unsymmetrical spray cones and irregular spray patterns. Partial clogging of the holes in the vortex plate or disk will do the same.
To increase the carrying distance of spray:
1. Increase the pump pressure by pumping faster.
2. Increase the pump pressure by using a smaller disk orifice. A smaller disk orifice without an increase in pressure will not increase the carrying distance.
3. Use a larger disk orifice, but at the same time maintain or increase the previous pump pressure.
4. Remove the vortex plate—this produces a solid jet stream suitable for spraying the tops of the higher trees and shrubs.
To increase the fineness of spray:
1. Increase the pump pressure by pumping faster; or
2. Increase the pump pressure by using a smaller disk orifice.
To decrease the quantity of discharge:
1. Use a disk with a smaller orifice; or
2. Decrease the pump pressure.
Dusting Equipment:
For small gardens, a light, inexpensive dust gun or bellows duster with a long tube and fishtail nozzle for directing the dust is practical. The duster should never be filled more than about half full of dust, as it will tend to come out in lumps when the duster is too full. A greater density and spread of dust can be obtained by removing the long tube. This is sometimes desirable when large, heavily foliaged plants are to be dusted.
Knapsack dusters of two types are available for larger gardens. The knapsack bellows duster is very effective and thorough for individual low plants or dwarf fruit trees. It wastes very little dust, as a cloud of dust is produced only when the bellows are constricted. The rotary fan-duster is excellent for vegetables growing close together in long rows. It is much faster in action than the bellows type of duster, but wastes more dust and may not do as thorough a job.
You dust continuously as you walk along, turning the crank. This duster is most effective when it is used to dust a row from both sides by going up and back on the same row with the dust hitting the foliage at an angle. Both dusters have valves which regulate the flow of dust and thus the density of the dust cloud.
The wheelbarrow duster is essentially the same in operation as the rotary fan-duster, except that the fan is propelled by a belt and pulley running from the wheel. It may be equipped with either two or four tubes with nozzles, and covers two rows at a time. Obviously, a better job can be done with two nozzles to a row than with one. One nozzle should be adjusted to blow the dust into the sides; the other into the tops of the plants. This type of duster is suitable for large vegetable gardens where plants grow close together in rows. It is rapid in operation, but usually takes a husky individual to operate it without tiring.
Pointers on Spraying and Dusting:
In the final analysis the wielder of the spray or dust gun, provided the equipment is operating perfectly, is the deciding factor in the success of his efforts; for the thoroughness and evenness with which he applies the sprays or dusts determine whether the pests will be controlled or the disease prevented. Spraying or dusting should be done methodically, with an eye to complete and even coverage of both sides of the foliage. An appreciation of complete and even coverage requires, in many cases, observation and continuous practice under the guidance of an experienced man.
In spraying the outsides of trees, treat them like solid objects. The spray gun should be moved vertically, like a paint brush, overlapping slightly with each upward and downward stroke of the gun. Hold the gun longer at the upward end of the stroke to be sure of getting sufficient spray on the upper foliage. Do not miss the ends of the lower branches—you may have to back away from the tree to get them.
In applying dormant sprays, the trunk, all branches, and twigs, especially their tips, should be thoroughly wetted from all angles. Failure to apply enough spray to a tree is a common cause of poor results. Wet the foliage, but do not cause the spray to run off. When sprayed correctly with hand-operated equipment, small to medium sized trees should take from 2 to 5 gallons of spray. Applications made on the same trees in the dormant season take about one-half as much spray.
When to Spray and Dust:
Sprays and dusts should be applied when they will do the most good. Dusts stick best if applied when the foliage is damp or wet and there is no wind. Dusts containing nicotine should be applied on dry foliage. Early morning or late evening is usually best for dusting conditions. Sprays should not be applied to wet foliage or in freezing weather in the dormant season.
Applications of sprays or dusts for diseases are best made before periods of wet rainy weather; otherwise as soon as possible after the wet weather has set in. It is easier to prevent a disease than to control it after it gets started. Recognition of the susceptible stages of insect pests is essential to timing your applications for most effective results.
Care of Equipment:
A little preventive care of equipment will make it last longer and save many a delay. Strain all solutions put into a sprayer through a cheese cloth. Small hard particles may prevent the valves from operating properly, or they may clog up the nozzle. Loss of pressure or lack of pumping action in sprayers may be due to dirt in the valves, sticky valves, or a worn-out, cracked, and dried-up plunger washer. These troubles may be avoided by washing the sprayer out immediately after each use with clean water.
Be sure to run the water through the nozzle for a few minutes to clean out the spray residue. Oil the leather plunger washer after each spraying to prevent it from drying up. Running a little kerosene through the sprayer will help clean dirty or sticky valves. If any parts on sprayers or dusters need oiling or greasing, be sure to do so before each operation.
Dust should not be left in metal dusters, as corrosion may begin. Oil is not necessary on the plunger washer of a hand dust gun. The parts that wear out most readily on a sprayer are the leather plunger washers and the nozzle disk orifices. Be sure to have replacements for them when you need them. When storing equipment for the winter clean it out thoroughly and oil or grease all working parts. Rubber hose should not be oiled as oil rots rubber.