Citrus Leafminer

 

 

 

Contents:

This webpage provides supporting documents to the discussion of biological aspects of citrus canker, as provided in Chapter 3 of the book. Also, more recent events are posted on this page.

The serpentine mines created by the citrus leafminer larvae is considered by many biologists to make a citrus plant to susceptible to the canker disease. The Department has shown images of citrus canker lesions within these mines.

As stated in the UF/IFAS circular:

Citrus leafminer greatly exacerbates the severity of citrus canker caused by Xanthomonas axonopodis pv. citri. This insect is not a vector of the disease. Nevertheless, leafminer tunnels are susceptible to infection much longer than mechanical wounds. Tunnels infected by canker produce many times the amount of inoculum than in the absence of leafminer. Control of leafminer should be optimized in areas where infection by canker is high. Natural enemies already present in Florida have responded to leafminer infestations, causing up to 90% mortality of larvae and pupae. These natural enemies include the introduced parasitoid Ageniaspis citricola that has established throughout most of Florida and is responsible for up to 30% of this mortality, mostly later in the year.

Map showing distribution of CLM

Chapters in book:

Chapter 3, Section 7, Citrus leafminer

Chapter 7, Section 13, pages 154 and 156.

Links:

University of California, IPM. 2010. Citrus Leafminer.

Michaud, J.P, 2002. Classical Biological Control: A Critical Review of Recent Programs Against Citrus Pests in Florida. Entomological Society of America.

(Review of biocontrol of CLM is provided on page 534. Statistics supporting the conclusion of successful biocontrol of CLM may be exaggerated according to the author)

Timmer, L.W., 1996. Biological Control of Citrus Leafminer Proves to be an IPM Success, UF.IFAS.

Hall, D.G. et al, 2010. Exacerbation of citrus canker by citrus leafminer Phyllocnistis Cittrella in Florida, Florida Entomologist.

Canteros, B.I, 2004. Management of Citrus Canker in Argentina. Proc. Int. Soc. Citriculture, 2004 Paper No 90.

 

Suppliers of Traps:

PHEROMONE TRAP and LURE SUPPLIERS

ISCA Technologies, Inc. www.iscatech.com

APTIV, Inc. www.aptivinc.com

 

Advances in Control of Citrus Leafminer

Rogers, M.E. and Stansly, P.A., 2006. Management of citrus leafminer, Citrus Industry.

Notes that imidaclorid may be an option, however article does not discus environmental impact on bees.

Hoy, M.A. et al, Parasitoids of CLM, Featured Creatures, UF/IFAS series, published in 2003, reviewed 2014.

2023–2024 Florida Citrus Production Guide: Citrus Leafminer

 

Citrus Leafminer

 

 

Observations as discussed in Florida's Citrus Canker Epidemic: Pieces of a Puzzle by David Lord

The tunnels left by CLM are easily identified in most citrus trees. They can not be mistaken for any other damage cause by an insect. Yet the 1998 Florida field study, which repeatedly surveyed residential citrus trees, did not include gathering any information on the presence of CLM. This seemed very odd, but an explanation is given in my book, on page 154, Chapter 9 under section 13, "The Department/ USDA field study narrative starts to fall apart."

Citrus leafminer causes minor damage. This damage can cause additional lesions in a citrus tree. However it seems to be an open question as whether the presence of citrus leafminer truly makes the dissemination of canker by windblown rain occur more rapidly or the transport over a larger distances. There seems to be an absence of experimental studies in these areas.

A citrus canker lesion in the mine created by CLM larvae will not appear as a circular brown lesion with a yellow halo. It is likely to be missed by inspectors. This would also be the case with other insect damage and wounds.

After CLM was discovered in Florida in 1993, grove and nursery owners likely took swift action to control citrus leafminer through application of insecticides. This was likely easy to do, as citrus has many known pests in Florida and grove owners routinely need to spray for insects.

While studies showed an increase in canker incidences in Brazil, corresponding to the introduction of citrus canker, it would seem there is an absence of corresponding studies to show a decline in canker once CLM is controlled.

Most horicultural guides recommend control of citrus leafminer. Systemic neonicotinoid insectides are effective against the Asian citrus psyllid, which vectors citrus greening and citrus leafminer. A very common pesticide is imidaclorprid with over one billion dollars in sales. It is a neurotoxin which can be ingested by beens through the pollen and nectar. The bees ability to forage may be impaired through ingesting the chemical. The EPA will decide by 2018 to continue to allow sales of this chemical as discussed in Chapter 10 of the book. It is current sold for commercial and residential use for a very wide range of insects and hosts.