Distribution, Pest Status and Fungal Associates of Euwallacea nr. fornicatus in Florida Avocado Groves

• Published in: Insects (Basel, Switzerland) Vol. 7; no. 4; p. 55
• Main Authors: Carrillo, Daniel, Cruz, Luisa F, Kendra, Paul E, Narvaez, Teresa I, Montgomery, Wayne S, Monterroso, Armando, De Grave, Charlotte, Cooperband, Miriam F
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14-10-2016; MDPI
• Subjects: Acremonium; ambrosia beetles; Coleoptera; Curculionidae; Euwallacea; Fusarium; Graphium; Morum; Persea americana; Scolytinae; symbiosis; Fusarium; ambrosia beetles; symbiosis
• ISSN: 2075-4450; 2075-4450
• DOI: 10.3390/insects7040055

Members of a complex of cryptic species, that correspond morphologically to the ambrosia beetle
(Eichhoff) (Coleoptera: Curculionidae: Scolytinae), were recently found attacking avocado (
Mill.) in Israel and California. In early 2016, an outbreak of another member of this species complex was detected infesting approximately 1500 avocado trees in an avocado orchard at Homestead, Florida. An area-wide survey was conducted in commercial avocado groves of Miami-Dade County, Florida to determine the distribution and abundance of
nr.
, to identify different populations of
nr.
and their fungal associates, and to assess the extent of damage to avocado trees.
nr.
were captured in 31 of the 33 sampled sites. A sample of 35 beetles from six different locations was identified as
. nr.
sp. #2, which is genetically distinct from the species causing damage in California and Israel. Eleven fungal associates were identified: an unknown
sp., AF-8, AF-6,
sp.
,
,
sp. and three yeast species. The unknown
isolates were the most abundant and frequently found fungus species associated with adult beetles and lesions surrounding the beetle galleries. In addition to fungal associates, three bacteria species were found associated with adult
nr.
. Visual inspections detected significant damage in only two orchards. A large number of beetles were captured in locations with no apparent damage on the avocado trees suggesting that
nr.
are associated with other host(s) outside the groves or with dead trees or branches inside the groves. More research is needed to determine the potential threat
nr.
and its fungal associates pose to the avocado industry and agricultural and natural ecosystems in Florida.