|
|
|||
|
ORGANIC SCALE CONTROL
© Frances Michaels
Scales are small sap-sucking insects that often go unnoticed by the gardener, but they can do damage out of all proportion to their size. Common scales include black scale, pink wax scale, cottonycushion scale, San Jose scale, soft brown scale, red scale and white louse scale. Scale tend to have small, round shells and are often found along the veins of leaves and the stems of plants. They look like small bumps and can be mistaken for part of the plant, as adults do not move.
Eggs are laid under the scale shell and immature 'crawlers' emerge. Crawlers can be moved around by wind, by ants, or by hitching a ride on a bird's leg. Scale in large numbers cause leaf yellowing, leaf drop and dieback of twigs and limbs. In very large numbers red scale can seriously damage or kill young citrus trees. Some scales secrete large amounts of 'honeydew', for example in a eucalyptus forest this can sometimes be seen as a gentle sticky rain. The honeydew causes problems by sticking to the lower leaves where it is fed on by a black fungus called 'sooty mould'. This makes a plant look unattractive and interferes with photosynthesis. Honeydew also attracts ants, which feed on it. The ants can 'farm' the scale, protecting it from predators.
BIOLOGICAL CONTROLS PHYSICAL AND CULTURAL CONTROLS LEAST TOXIC CHEMICAL CONTROLS
Insecticidal
soap sprays such as
Natrasoap
work by blocking the breathing pores and
dissolving the scales outer covering so If you plan to spray, wait for settled weather with little wind and no rain. Spray in the early morning or late afternoon to avoid burning the leaves and to reduce the impact on beneficial insects Wettable sulphur or lime sulphur can be sprayed in winter to control white louse scale on citrus.
|
|||
|
DISCLAIMER: No liability will be accepted by Green Harvest, its owners or employees as to the accuracy of any information. No responsibility will be taken for damage to property or persons due to information given about a product or technique. No responsibility will be taken for the loss of a crop or income due to information given about a product or technique.
Copyright © 2001, 2004, 2005, 2006, 2008 Green Harvest |