Small beetle, big problems
After wet weather and when fruit are ripening, a small beetle can cause problems for fruit producers.
- Also known as dried fruit beetles
- 2-3 mm in size, and
- attack a wide variety of hosts including stone fruit, persimmons, fallen citrus, apples, and figs.
- They do not breed in fruit on the tree.
- Adults lay eggs in rotting or damaged fruit on the orchard floor.
- Mature larvae emerge from the fruit and pupate in the ground.
A vector of brown rot - Carpophilus beetles are also a vector of brown rot. A fungal infection that results in rapid fruit rot both on the tree and also during the post-harvest storage period.
Adult beetles emerge from the pupae and attack fruit in late spring and summer. It takes about a month in summer to develop from egg to adult so there are many generations per year.
It tends to become a pest when there is a run of days above 20 degrees, that's when to start trapping. An attract-and-kill system using synthetic aggregation pheromone plus food-attractant provides effective protection of ripening crops, when deployed 6–8 weeks before the onset of fruit colour change.
Early in the season because beetle flight activity is high but food supplies are low. Flight does not occur at temperatures below 18oC.
The most recent Australian research by DPI Victoria and Horticulture Australia recommends that wide-area attract-and-kill treatment is adopted in orchards with high Carpophilus spp. populations, plots with less-susceptible varieties surrounding susceptible plots should be treated with 2 attract-and-kill traps per hectare deployed 6–8 weeks before the susceptible block begins to ripen.
As Carpophilus beetles can move several kilometres, area-wide cooperation is needed for most effective control. Growers should inspect fallen fruit to assess beetle activity and the potential for damage. Good fruit fly control will ensure that there are less damaged fruit on the tree or on the ground.
Orchard Hygiene is very important in controlling this pest. To remove overwintering populations of Carpophilus spp remove all fruit from tree and ensure a thorough mulch of all fruit remaining on orchard floor. If no hosts are available they overwinter in cracks in the tree, under bark or in mummified fruit.