Pest Identification

Identifying different life stages

Codling moth undergo complete metamorphosis.

Eggs are pinhead size (1-1.2mm in diameter), flat and oval.  They are translucent when first deposited turning white later.  They are laid singly on fruit or on upper surfaces of leaves near fruit and are difficult to spot in the orchard.

Larvae are 2mm long on hatching and pale white with a black head.  They are 13mm long when fully grown and tan to pink with a brown head.

Pupae are 10-12mm long are brown and are surrounded by a silk cocoon.

Adults are a long mottled grey and brown moth, 19mm across with expanded wings and 9mm long with wings folded.  Wings show bands of alternating grey and white with a bronze to copper spot on the tip of each forewing.

Life Cycle

Depending on the climate, codling moth can have two, three and sometimes four generations per year. Codling moths overwinter as a pre-pupae stage within silken cocoons. These are located under bark on tree trunks or lower branches and in soil or debris around the base of the tree. They can also overwinter in orchard waste piles and fruit storage bins. Overwintering larvae are able to withstand low temperatures though they will be killed by frost. Pupation occurs within the cocoons in early spring when temperatures exceed 10°C in early spring, emerging as adult moths. Mating occurs when the sunset temperatures exceed 17.5°C. Following mating each female deposits 50 to 100 eggs singly on leaves, twigs or fruit. Eggs are typically laid in the first few days after emergence and mating when the temperature reaches 15°C or higher, taking between 6 to 20 days to hatch. On hatching, larvae bore into a single fruit or developing nut and feed for between 3 and 5 weeks. After completing development here they exit by dropping from the tree. The life cycle is continued in protected sites under the tree with some crawling up the trunk to pupate in bark. Pupation follows a brief cocooned period unless temperatures are sufficiently low to induce overwintering of the cocooned larvae.

Codling moth development occurs between the lower and upper temperature thresholds of 10° C and 31° C with development being proportionally higher with higher temperatures. Knowledge of daily site temperatures and these development rates allow the emergence and development of codling moth populations to be successfully predicted using a unit known as temperature degree days. A pheromone or sex-attractant trap can be used to determine exactly when the codling moth is flying. Sticky traps with the codling moth pheromone lure should be hung in the tree at bloom, placing one pheromone trap every 2 hectares or two per orchard. Key to the predictions is the Biofix or the beginning of consistent moth flight. It is the biological marking point from which the rest of the development of the insect is measured. Using this starting point at the beginning of the season Biofix is determined when either 1 moth is recorded for every 2 hectares of an orchard or two moths are found in one trap on two consecutive nights. With sufficiently precise recordings accuracy of spray treatments can be greatly improved and population numbers well contained. Table1: Codling Moth emergence and corresponding degree days through out a growing season. (British Columbia model, 1986)

Table1: Codling Moth emergence and corresponding degree days through out a growing season. (British Columbia model, 1986)

Insect stage that causes damage

Codling moth damage to fruit or nuts is always caused by developing larvae whether damage is of the deep entry or surface sting type.

When and where to identify

Adult moths emerge around the time fruit trees are in bloom. They become active for a few hours at dusk when evening temperatures are between 13-20°C. Peak flight occurs approximately two to three weeks after full bloom and may continue for several weeks.

Geographical location

With the native home of codling moth considered to be south eastern Europe, the codling moth is now a cosmopolitan insect occurring in almost every country where apples are grown.

Damage

Timings

Fruit attacked early in spring often drops while larval development can still be completed in the fallen fruit. Further attacks will occur with each subsequent codling moth generation. Left unchecked damage can be almost continuous due to the high fecundity of the pest and the multiple generations in a year.

What and where

Adults can be caught in pheromone baited delta traps (Figure 1). There periods of the year adults are active will vary depending on geographical location but typically from to harvest.

Larvae can be found within the fruits. Failed fruit penetration can be seen as a ‘sting’ (Figure 2). Inhabited apples can be identified by the presence of brow sticky frass emerging from an entry hole on a fruit (Figure 3). When cut open it is possible to find the larvae feeding within the fruit (Figure 4).  

Susceptible plant species

Codling moths are major pests of a variety of top fruit including pome fruit such as apple, pear, plum, quince, asian pear, crab apple, hawthorn, cherry, walnut, apricot and peach.

Crops Affected by Codling Moth

Codling moths are major pests of a variety of top fruit including pome fruit such as apple, pear, plum, quince, asian pear, crab apple, hawthorn, cherry, walnut, apricot and peach.

• Apples
• Pears
• Nuts

Nemasys^®C

Nemasys^® C based on the beneficial nematode Steinernema carpocapsae and provides control of Codling moth (Cydia pomonella) in pome fruit, including apple, pear, quince, asian pear, crab apple, hawthorn and cherry.

Nemasys^®C contains nematodes in their vigorously infective juvenile stage. Once applied these nematodes seek out and control the overwintering pre-pupae of codling moth. It is also able to control the larval stages of chestnut moth (Cydia spendana), peachtree borer, cranberry girdler, dogwood borer and clearwing borer.

The codling moth life cycle is synchronised over winter by the presence of 5th instar larvae, these larvae are in cocoons in the tree trunks and in the soil. This overwintering stage is very susceptible to nematode attack.

Nemasys^®C applied after harvest as a cleanup application can significantly reduce pest pressure the following year, allowing mating disruption to be used or delay the start of chemical or virus control programmes.

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