Biology/ID

Geographic Distribution and Arrival in California

The Black Fig Fly (BFF) is a newly identified pest in California that exclusively reproduces on figs (Moraceae: Ficus carica). The BFF is native to the Mediterranean and Middle East, but has subsequently spread to South Africa (in 2007) and Mexico (in 2020). The first report in the US was in June 2021 from southern California.

Life Cycle and Identification

Adults

Adult BFF are glossy black, 3.5–4.5 mm in length, with reddish eyes and brown legs. They attack fig fruit and prefer green, immature/unripe fruits, but can sometimes lay their eggs on ripe ones as well. The unripe figs can be attacked as soon as they reach 0.4 inches in diameter, but most of them are attacked a bit later. The adults are also known to feed on sweet exudates sap from overripe fig fruits, and the milky latex secreted by figs from injured plant parts. Females oviposit directly into the ostiole (eye) of unripe fig fruits.

Larvae

Larvae emerge from these eggs and feed internally on the syconia (fruit) tissue. The larvae have an 11 segmented body which is less than 0.04 inches in the first larval stage and about 0.28 inches in the last stage. Larval feeding damages the fruit tissue and causes fruit to prematurely drop from the tree, which can sometimes be mistaken for natural fruit shedding or fungus disease. For those varieties of figs that become dark when ripe, the very first symptom can be a purplish-red zone on the premature green fruits while they are still on the tree. 

Pupae

As they near completion of development, the BFF larvae exit the fruit (leaving behind a small hole) and drop to the ground, where they then pupate in the upper 4" of the soil. BFF pupae are approximately 0.16 inches in length. Larval exit holes can be found on fruit in the tree and on the ground.

Multiple Generations per Year

BFF is multivoltine and can have between 4-6 generations per year depending on environmental conditions. The entire life cycle can be 18-20 days in summer and around 48 days in spring, depending on the temperature (i.e. it will be shorter in warmer areas and longer in cooler ones). Specific temperature thresholds, degree-day requirements, and the number of generations in California are all still unknown, but work is now underway to better characterize and estimate this (see "Current Research").