EQUIPMENT used for processing flower seeds includes a stationary thresher, a table model of the air-screen machine, a laboratory blower, and a specific gravity separator.

Conventional seed-cleaning equipment is used for sweetpea seeds. Vines are cut and left in a windrow to dry. Then they are lifted from the windrow and threshed with a combine that has a windrow attachment. Threshed seeds are cleaned on an air-screen cleaner to remove straw, leaves, weeds, and other large materials. The seeds are passed through another airstream that removes light trash. Light or shriveled seeds are removed with a specific gravity separator.

HAND LABOR is used often in producing and processing seeds of the new petunia hybrid. The seeds are planted by hand. Seedlings are transplanted by hand. Pollination, cultivation, harvesting, threshing, and packaging are done by hand. These seeds have sold for 7 thousand dollars a pound wholesale.

Seeds of petunia, salvia, primroses, marigold, zinnia, nasturtium, and many other flowers are harvested by hand, dried, and then processed in stationary threshers of many sizes up to field combines. Small air-screen and gravity separators and some handpicking are used in processing them.

Seeds of foxtail, snapdragons, asters, and similar flowers are cut before the seeds reach the shattering stage with a special swather that deposits the seeds on a canvas, where they are left to dry. The seeds are covered with canvas at night to protect them.

These seeds are cleaned after drying on the air-screen blower and gravity separators. Low-temperature, forced-air driers are used to reduce the moisture content to a safe level.

Flower seeds usually are processed in small volumes on small equipment, because only small amounts of seed are used each year. Many types of flower seeds lose vitality when they are stored more than a year. Seeds of some flowers that are properly dried and stored at moderate temperatures and humidities can be kept several years.

FUNGICIDES used to be applied in wet treatments, but the practice was unsatisfactory.

The development of dry-dust treatment was a big advance. Copper carbonate, introduced into the United States about 1920, mostly replaced the wet treatments as a control measure for many cereal diseases, especially stinking smut or bunt of wheat. Various types of equipment were developed for its application, notably a hand-operated, barrel-type treater, in which the seeds and the dry fungicide were mixed by a tumbling action.

Continuous-type dust treaters were developed and used many years. They have a fairly high capacity in bushels of seed treated per hour, but the problems, discomforts, and dangers involved in treating, handling, and planting dust-treated seed were many.

These objectionable features were overcome to a certain extent with the introduction of organic mercurials formulated as wettable powders for application in slurry-type treaters.

In it, the fungicide is mixed with water to form a thick, soupy suspension. Slurry machines are equipped with an adjustable hopper to control the flow of seeds into the machine, a slurry tank with a mechanical agitator to stir the mixture constantly, a positive seed and slurry metering device, and a short mixing auger that mixes the fungicide slurry and seeds and also moves the treated seeds to the discharge spout of the machine.

Slurry machines with output capacities up to 600 bushels of treated grain an hour are available. They usually are powered by small electric motors. Seeds of cereal grains, legumes, grasses, and vegetables can be treated in the basic machine. It can be modified as to seed hopper and mixing auger to treat delinted or fuzzy seed of cotton.

Special treaters have been developed for the application of concentrated liquid fungicides and insecticides directly to seed without water dilution. Two such treaters are available. One is of a rotating drum type; the other, a mist type.

The former has an adjustable seed hopper, which regulates the flow of seed into the machine; a small fungicide reservoir, from which the fungicide is metered into the machine; a storage drum of fungicide connected to the machine through a series of hoses and a centrifugal pump; a positive seed and fungicide metering device; fingerlike tubes at the drum inlet, which dispense the fungicide to the seed; and an inclined mixing chamber, whose adjustable baffles regulate the time the seed is retained.

Some models of the drum machine can treat up to 700 bushels of grain an hour. Seeds of cereal grains, legumes, grasses, cotton, and vegetables can be treated. Attachments enable the simultaneous application of liquid fungicides or insecticides and wettable powders or liquid fungicides and liquid insecticides. The treater has a small electric motor.

The mist-type treater is designed to apply low dosages of liquid fungicides. It has an adjustable hopper that regulates the flow of seeds into the machine; a positive metering device; a seed-dispersing cone; and a rapidly spinning disk, which breaks up the liquid fungicide into droplets. The dispersion cone causes the seeds to fall in a layer through the droplets.

A treater with three rotating disks in series was designed to provide more complete and uniform coverage with concentrated liquid fungicides. It is well suited to the application of wettable powders. The fungicide needed to treat a mass of seed is divided into three parts, each of which is broken up into a fog by a separate disk. The triple treater can also be modified to apply one, two, or three different formulations at one time.

A continuous-spray type of treater has come into extensive use for treating seeds of sugarbeets. Coverage obtained in an experimental model was nearly coo percent. This method does not have the objectionable features of dust machines that once were used to treat sugarbeet seeds.

The continuous spray-type treater has an adjustable seed metering device, which is equipped with a switch that is activated when the hopper is empty; a tank containing the treating mixture, also equipped with a signal device to indicate when the mechanical agitator is in operation; pressure gages that indicate the pressure in pounds per square inch at the tank end and nozzle end of the pressure system; one flat fan nozzle; an indicator system that is activated when the flow of the treating mixture has fallen below a desired rate; a rotating cylinder about 6 feet long, big enough to allow good distribution of fungicide, and open at both ends; and a corrugated liner inside the cylinder. The fungicide mixture is placed under pressure in the reservoir tank by compressed air. The treating mix flows through the lines to the nozzle and is sprayed on the seeds.

The fungicide mixture is sprayed on decorticated seeds of sugarbeet at the rate of 2 quarts per hundredweight of seeds. This applies 4 percent moisture to the seeds.

The treater drum or cylinder is powered by an electric motor of three-fourths horsepower. Its capacity is 2,500 to 3,500 pounds of treated decorticated sugarbeet seeds an hour. The treated seeds are elevated in airlift elevators to storage tanks, from which the seeds are bagged.

Coloring agents or dyes are added to the treating mix to denote specific treatments green for seeds treated with wireworm repellant-fungicide; red for seeds treated with wireworm repellant; and yellow for fungicide-treated seeds. The colors also indicate the uniformity of coverage.

The high price and capacity of the machine may limit its general use to processors who handle large amounts.

The coverage obtained with most commercial seed-treating machines is incomplete. The coverage provided by the slurry-type machines, for example, is 75 to 90 percent. Drum and triple treat mist-type machines give about 80-95 percent coverage. The spray-type treater provides coverage of 96 to 100 percent.

LAURENCE H. PURDY is a plant pathologist in the Cereal Crops Research Division, Regional Smut Research Laboratory, Pullman, Wash.

JESSE E. HARMOND is Head, Small Seed Harvesting and Processing Section, Agricultural Engineering Research Division, Corvallis, Oreg.

G. BURNS WELCH is an agricultural engineer, Mississippi State University, State College, Miss.