KNOW YOUR PEST

Four key features to look out for when trying to identify FCM in traps and to differentiate them from other moth species that might be present

• a “plume” of greyish white scales or a white dot on the forewing (Figure 1)
• a patch of scales in the middle of the forewing that are raised and light brown/rust-coloured (Figure 2)
• a darker patch of scales at the bottom of the forewing, forming what looks like a question mark (Figure 3)
• a broad semi-circular band of darker scales found in the middle of the forewing, not as prominent as the other three features (Figure 4) (Moore 2022; EPPO 2019).

In some instances, FCM may lose their scales and these four distinguishing features may not be as clear, as shown in Figure 5.

In this case, a few steps can be followed to try and identify the moth

• Screen the variety of moths in the sticky trap and determine if they match the general size of FCM (8–12 mm).
• Observe the outline of FCM’s appearance and try and match it to those moths that fit the size of FCM.
• If the sample is a male FCM, as should always be the case in pheromone traps, it should display a distinguishing feature that is not found on other species, a semi-circular pocket of scales on the hind wings (Figure 6). Another feature of male FCM is that they have tufts of black scales on their hind legs, which are not seen on other species (Gilligan & Epstein 2014).

It is a good idea to furnish trap monitors with the photographs and guidelines provided in this article, to assist with more accurate identification of FCM.

In instances where scouts or growers are not certain of the identification of these apparently dull adults, please contact your local pest expert or send any queries through to Tammy Marsberg at CRI, tammy@cri.co.za.

References

EPPO (European and Mediterranean Plant Protection Organization), 2019. PM 7/137(1) Diagnostic standard Thaumatotibia leucotreta. EPPO Bulletin. 49(2), 248 – 258. Gilligan, T.M., and M.E. Epstein. 2014. Screening aid: False codling moth, Thaumatotibia leucotreta (Meyrick). Identification Technology Program (ITP), USDA-APHIS-PPQ-S&T, Fort Collins, CO. 6 pp. Gilligan, T.M., M. Epstein, and K.M. Hoffman. 2011.

Discovery of false codling moth, Thaumatotibia leucotreta (Meyrick), in California (Lepidoptera: Tortricidae).

Proceedings of the Entomological Society of Washington. 113(4): 426 – 435. Moore, S.D. 2002. The Development and Evaluation of Cryptophlebia leucotreta Granulovirus (CrleGV) as a Biological Control Agent for the Management of False Codling Moth, Cryptophlebia leucotreta, on Citrus.

Ph.D. Thesis, Rhodes University, Grahamstown, South Africa. Moore, S.D. 2022. Moths and Butterflies. Chapter 3: False codling moth. Citrus Research International IPM Production Guideline. Volume 3. Part 9: 1 – 10.