PRACTICAL GARDENING

Press, Volume CVI, Issue 31344, 14 April 1967, Page 8

PRACTICAL GARDENING

Sfitciallf mint* for "Tko Proto'* bj :

M. LUSTY

immediate outer ring because as the mycelium grows further out it releases nitrogen from the organic matter in the soil, stimulating grass growth. Varies in Size The fairy ring starts as a small spot and gradually extends outwards. It can vary in size from a few inches to many yards in extent. Their life is more or less indefinite and some rings are exceedingly large. Some have been calculated to be about 400 years old. A ring tends to break up when unfavourable conditions are met such as poor soil or an obstruction such as a rock.

Eradication is difficult, time-consuming and can be costly, depending on the type and extent of the ring. The main difficulty lies in obtaining adequate penetration of a fungicide into the soil to achieve a kill. The most suitable time of the year to carry out treatment is when the grass is in active growth in spring or early autumn. At these times the rings are more clearly visible. It is usual to spike the intermediate area with a solid or hol-low-tined work, coring iron or even a crowbar to a depth of about 9in. An 18in ring outside the intermediate ring should be treated. Several controls have been claimed to be effective and their effectiveness would undoubtedly depend on the length of time that the fungus has been established, which type is present, prevailing conditions and thoroughness of the application. Even then it may be necessary to give follow-up treatment. Suggested Controls

Possible controls are: Malachite green, 1 ounce to 28 gallons of water to which has been added some spreader. Application to the spiked area should be at the rate of approximately one gallon a square yard. Sulphate of iron, 4 ounces to a gallon of water applied as a drench followed by liming. Bordeaux mixture, using 61b of copper sulphate to 41b of hydrated lime dissolved in 25 gallons of water and applied as a drench. Dithane M 45, at the rate of 4 ounces to 12J gallons of water and used at fortnightly intervals throughout summer, applying one gallon of the mixture to every 100 square feet Instead of spiking the inter-

mediate ring the turf of the whole ring can be removed and carefully carried away. The underlying soil is then forked over, incorporating calomel corrosive sublimate.

Probably the best method employs the use of formalin which is most commonly applied at the rate of 1 pint in 40 gallons of water, until the soil is saturated. This should be applied to spiked or excavated ground where the turf has been lifted. The treated strip is then covered with sacking or polythene sheeting to prevent the fumes escaping. These are left in position for two to 10 days depending on the soil condition and prevailing weather conditions—warmth being more conducive to quicker gaseous spread.

After removal of the covers the area should be forked over to aerate the soil and subsequently resowing is necessary.