Winter spraying

Winter spraying calcium sulphide (200-250 kg/ha) is used for this. Spraying must be carried out during complete winter dormancy (i.e. before the first green leaf appears). At this high concentration the calcium sulphide solution destroys the scale insects. It also controls spider mites and other overwintering stages. 

Amount used 15-20% as a winter spray (in absolute winter dormancy) 10-20 kg/ha against scab... 

Formulations of parathion with mineral oils have proved to be very effective as winter sprays against various hibernating forms of orchard pests. It is particulary potent against plant lice, flies and caterpillars, killing these pests in concentrations as low as 0.0001-0.0008%. It is hazardous to bees. Spraying with parathion at blossom time is therefore not permitted. 

Petroleum Oils. When satisfactorily stable kerosene—soap—water emulsions were produced in 1874, dormant (winter) oil sprays became widely used to control scale insects and mites (1). The first commercial emulsion or miscible oil was marketed in 1904 and by 1930 highly refined neutral or white oils, free from unsaturated hydrocarbons, acids, and highly volatile elements, were found to be safe when appHed to plant foHage, thus gready enlarging the area of usefulness of oil sprays (see Petroleum). 

Winter-grtin, n. wintergreen oil of winter-green ivy myrtle, periwinkle, -kresse, /. winter cress (Barfearea). -spritzung, /. (Agric.) dormant spray. 

Hooper, M.J. et al. (1989). Organophosphate exposure in hawks inhabiting orchards during winter dormant spraying. Bulletin of Environmental Contamination and Toxicology 42, 651-660. 

A field trial during the winter of 1981-1982 employed a fully automated enclosed design. It utilized fans to deliver cold outside air onto the water surface. The air is conducted to the water surface within polyethylene tubes sewn from sheeting. The outside temperature controls the frequency of water spraying. 

A field operator exposure study was designed to accommodate the chemical properties and the use pattern involved in the treatment of potato crops for protection against the Colorado potato beetle. Fifteen farmworkers experienced in the use of tractor-drawn sprayers for application of crop protection materials to crops were selected. All were adult males. To avoid production of a large quantity of treated potato crop prior to registration of the product for sale, the trials were performed on stubble fields after harvest of winter wheat crops in a potato-growing area of southern Ontario. This allowed the use of typical farm spray equipment and a typical duration of exposure for a complete shift of work. 

Henle, K. 1988. Amphibian and reptile fatalities caused by chlordane spraying Victor. Natural. 105 216-217. Henny, C.J., L.J. Blus, and R.A. Grove. 1990. Western grebe, Aechmophorus occidentalis, wintering biology and contaminant accumulation in Commencement Bay, Puget Sound, Washington. Canad. Field-Natural. 104 460-472. 

Black knot is a common disease of plum trees. This fungal infection produces swollen, knobby black galls on branches. Prune out affected branches during the winter, then spray lime-sulfur as buds swell in spring and again... 

What to do Grow resistant cultivars. Mulch under trees to stop soil from drying out Water trees in dry weather. In winter, cut out infected shoots. In spring, remove infected leaves and shoots. Spray with seaweed extract to promote strong growth. Fungicide spray Sulfur, although it can harm some apples. Check the label before use. 

What to do Look for resistant cultivars. In fall or late winter, prune off infected limbs, 6-12 in. (15-30 cm) below the knots disinfect pruners in between cuts with a 10% bleach solution (1 part bleach to 9 parts water). Destroy the prunings. Remove any wild plum or cherry trees nearby. For persistent infections, apply 2 sprays of lime-sulfur, 7 days apart, before the buds begin to grow in spring. 

All test treatments were applied approximately 1 month ahead of hatching and over a 2-day period. The writers (5) have shown that mite winter eggs become increasingly more susceptible to oil sprays as the hatching time approaches. Possible errors arising from this cause were avoided in these studies by limiting treating time to a 48-hour period. 

Potassium gibberellate (Gibrel, a solution of potassium gibberellate supplied by Merck Co., Inc.) was applied three times (September 17, October 1, and October 15). These spray treatments consisted of 10, 20, 30, 40, 50, and 100 p.p.m. of potassium gibberellate plus an unsprayed check. These plots, as well as all others in the field studies, were kept under observation until the winter mulch was applied in December 1958, and observations were continued in the spring of 1959 when the mulch was removed. 

---