Driedfruit Beetles

Driedfruit beetles, also known as sap beetles, are a complex of several closely related species in the family Nitidulidae that have similar life histories and resemble each other in appearance. The driedfruit beetle, Carpophilus hemipterus, is the most common species, but the Freeman sap beetle, C. freemani, and the confused sap beetle, C. mutilatus, are also common and can be the most abundant in some orchards. Carpophilus marginellus, Haptoncus luteolus, and Urophorus humeralis are sometimes present in lesser numbers.

Adults are small brown or black beetles with or without lighter spots on the wings, depending on the species. They range in size from 0.1 to 0.2 inch long and have clubbed antennae. The wings do not cover the last two to three abdominal segments. Larvae are white and 0.1 to 0.2 inch long when mature. They have tan head capsules, three pairs of true legs, and two hornlike structures on the anal end.

Driedfruit beetles damage figs in three ways: their presence in the fruit causes downgrading or rejection of the fruit, they transmit spoilage organisms that cause fruit souring, and they increase the attractiveness of the fruit to other pests such as vinegar flies and navel orangeworm.

Early harvest and orchard sanitation can help reduce the damage potential of these pests as can the use of less susceptible varieties. Trapping of driedfruit beetles in large containers containing cull fruit, water, and yeast as a bait may be effective in reducing the population if done before the fruit ripens and becomes attractive. Once the fruit begins to ripen, insecticides may be necessary.

Because driedfruit beetles can feed on moldy, mummified fruit left in the orchard during winter, remove all cull fruit from the orchard as soon as possible after harvest to reduce the overwintering population. Harvest early and rapidly to remove infested fruit from the orchard before the larvae are mature enough to drop to the soil and pupate, thus preventing the subsequent emergence of adults from the soil to infest later crops. Fumigate first crop Missions, Conadrias, and Adriatics, as well as Calimyrnas, which are harvested over a period of up to 2 months. Driedfruit beetles that are not removed by early harvesting will complete development and emerge to infest the later maturing portion of the crop.

Driedfruit beetles have an extremely wide host range and will infest any ripe or fermenting fruit. They can fly distances of several miles to find a suitable host. If possible, locate fig orchards as far as possible from other host orchards such as stone fruits and citrus.

All commercial varieties of figs are susceptible to infestation by driedfruit beetles. However, varieties that have small eyes, such as Missions, are usually less affected. The major commercial drying variety, Calimyrna, has a large eye that renders it easily infested. It also sets fruit after the first crop of other varieties in which the beetle population builds up. A relatively new variety, Tina, has similar fruit characteristics to Calimyrna but has a smaller eye and does not appear to be as susceptible to driedfruit beetles.

To monitor, place small bait traps in the orchard before the crop begins to ripen. Bait the traps with cull fruit, water, and yeast. Remove beetles from the traps twice a week and replenish the water as needed.

Spray the trees when trap counts begin to drop off; driedfruit beetles are infesting the fruit at this time. Several sprays may be necessary under heavy beetle population pressure. Treat from a few hours before to just after sunset, which is the period of greatest beetle activity.