Red scale is a common pest found in citrus plantations, these armoured scales are found on wood leaves and fruit. Each female scale can produce nearly 150 crawlers (larvae) which hatch from under the scale at two to three per day.
They are spread throughout the plantations by physical means on man and animals or birds. The very short lived male has wings and will hatch mate and die.
Scales are a sucking pest that will attack all parts of the citrus tree causing damage to the trees such as leaf yellowing and dieback. In periods of drought stress heavy infestations can cause tree death. The highest risk is at the end of the summer.
Timed releases of high numbers of the parasite Aphytis melinus have given economic levels of control of the red scale. The parasite is susceptible to pesticides so careful choice of chemical controls is critical to successful use.
The timing of releases of the parasites can be programmed in areas where the practice is well established, also pheromone traps used to monitor male flights can improve timings of releases.