Scientific name: Zeuzera pyrina
Common name: yellow drill, fruit borer
Affects: Bone and pip fruit trees, olive tree, and other tree species.
State Size Features
Larva Up to 60 mm Body yellow with black dots and black head.
Adult 35-70 mm Thorax and white wings with black spots. Black abdomen with some white stripes.
Egg 1 mm Yellowish color.
Very high importance in pears and apples.
In olive tree it has secondary importance.
Adult Pupa Larva Egg
Duration (d) - 10-20 15 5-10
Adults fly from June to September-October. The males appear a few days before. The females, once they mate, perform the laying in groups of eggs in the bark of the trunk or branches (sometimes in the ground). The neonatal larvae are grouped for a few days protected by silk filaments. Then they go to the tender areas of the plant and make small galleries or feed on leaves, depending on the species affected. After this first feeding they are already prepared to penetrate thicker wood, with which they leave the first galleries for the same place that they have entered and go to the branches and the trunk. In winter its activity ceases or is reduced. With the arrival of spring manifests its greatest activity to complete its development and pupate (from April-May to August) inside the gallery.
In the coldest areas of the peninsula it is common for a small percentage of the population to respond to a biannual cycle, with adults appearing the following year but one month before (May-June) than individuals of the annual cycle.
Symptoms / Damage
Galleries in branches and trunk.
Sawdust and / or reddish droppings at the base of the trunk.
Very serious damage in young plantations.
Weakening of the branches that can be split by the action of the wind, subject of special interest in public gardening.
As it happens in all the plagues that practice galleries, the chemical treatment is complicated by the difficulty of which pesticide and caterpillars come into contact.
End of spring-summer, from the hatching of eggs and first feeding when the caterpillars are in shallow areas and before they enter the interior of the coarse wood.
Treatment applied on the trunk and branches by spraying.
The active substances to be used in stone and pip fruit trees are the pyrethroids: alpha cypermethrin, beta-cyfluthrin, cyfluthrin, deltamethrin, esfenvalerate (only in pip fruit), lambda-cyhalothrin, zeta-cypermethrin.
There is an added problem and that is that the flight period is very long, and as a consequence the birth of the larvae. This means that treatments must be repeated every two weeks from the first hatching at the end from spring to the end of summer.
There are some organisms that affect this insect, although they are not able to control it properly.
Birds (eat caterpillars before they penetrate the wood), Hymenoptera of the family Ichneumonidae.
- Cultural measures
The caterpillars can be removed manually by barking the area with symptoms and extracting the individuals with a wire (or by pruning if necessary). Advisable in isolated cases.
It is necessary to place pheromone traps for the capture of adults in order to track populations and act in a timely manner.
For massive trapping place 10 traps / Ha.
Keeping the plantation healthy and vigorous will make the attack of the plague difficult.
This plague can bring with it the appearance of scolitids, which end up weakening the tree.
It is convenient to eliminate very affected feet. It is important at this point not to leave wounds on the bark of the trees so we will paint them with waxes or suitable polymers.