Grease for Apple Trees
Sticky barriers known as grease bands and "fruit tree grease" are widely used in England to protect apple, plum, pear and cherry trees from wingless moths and other pests. Ornamental shrubs and trees, including roses, lime, oak and sycamores, are often attacked by the same offenders.
Attach grease bands and apply paint-on grease in late October, reapplying as needed through the following April.
Several species of moth attack fruit trees in a similar fashion. Wingless females of winter moth (Operophtera brumata), March moth (Alsophila aescularia) and mottled umber moth (Erannis defoliaria) emerge in the soil from their pupal or chrysalis stage, then climb trees to mate and lay eggs in cracks and crevices of tree bark and branches. Caterpillars eat the leaves of many deciduous trees and shrubs from late March into June. But tree grease cannot protect against the codling moth, a midsummer pest with winged females that causes maggoty apples.
Place grease bands on trunks and also on tree stakes--another route into trees for moths--completely encircling the tree about 18 inches above the soil surface in late October, before adult moths begin to emerge in November. Remove long grass, weeds or other vegetation near trees that may reach above the band, to avoid providing another option for moth migration.
Fruit Tree Grease
Fruit tree barrier glue or grease is more effective on older trees with ridged or fissured bark. Pests can crawl under grease bands, but not grease painted directly onto tree bark. Tree grease, an extremely sticky but nontoxic substance made from rapeseed oil, traps wingless female moths or deters them as they attempt to lay their eggs high in the trees, near a ready food supply for caterpillars. Apply fruit tree grease with a small paintbrush or an old kitchen knife.
You can use barrier glue or fruit tree grease to trap earwigs in spring and summer, and to capture ants and other crawling pests. Ants will "farm" and protect aphids and scale insects once established in trees. Stop ants, earwigs and other unwanted guests by periodically applying fruit tree grease between May and September. Grease bands also have broader usefulness.
Many fruit tree growers also apply a plant oil-based winter wash to dormant trees in December or January to kill any pests overwintering on and in the tree bark. Tar-oil-based sprays are no longer legal to use in the United Kingdom. Nontoxic contact sprays made from rapeseed oil and newer garlic-based sprays are available in garden centres.