Update on cryptic species or biotypes of the Bemisia tabaci (Gennadius) whitefly complex in the Dominican Republic

Authors: SERRA, COLMAR - Dominican Institute For Agricultural And Forestry Research (IDIAF); McKenzie, Cindy; OSBORNE, LANCE - University Of Florida

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2019
Publication Date: 7/8/2019
Citation: Serra, C., McKenzie, C.L., Osborne, L. 2019. Update on cryptic species or biotypes of the Bemisia tabaci (Gennadius) whitefly complex in the Dominican Republic {abstract]. 55th Annual meeting of the Caribbean Food Crops Society, July 8-12, 2019, Bávaro, La Altagracia, Dominican.

Interpretive Summary:

Technical Abstract: Bemisia tabaci (Gennadius) is a large cryptic species complex whose members are particularly invasive pests of hundreds of economically important commodities including cotton, vegetables and ornamental crops. In 1995, dominant biotypes A and one not determined (X) were identified in five localities of the northwestern zone of the Dominican Republic. Biotype B was present in only two localities in low numbers, having in a few years widely displaced the others. A toxicity study conducted in 2015 on the reaction of Bemisia tabaci populations from different locations showed very high levels of resistance against insecticides of important groups. It was suspected an eventual entry of the Q biotype with a very high resistance to insecticides. To determine the presence of different biotypes in different localities and host plants, adults were collected in vials in ethanol (95%) for transfer to the United States Horticultural Research Laboratory of the USDA-ARS. Primers for the polymerase chain reaction (PCR) specific to cryptic species (biotype) were used: as a combined reaction (sets of 3 primers were used in the reaction of each whitefly) that amplify in unique regions of the mtCOI gene Within each species: MEAM1 (B), New World (NW) and MED (Q). Each pair of primers produces products of different sizes depending on the source of the isolated template DNA and does not require DNA sequencing. In the electrophoresis gel, the specific fragment of the amplified species will show a band for MED at 303 bp, NW at 405 bp and MEAM1 at 478 bp, which makes it very easy to distinguish between three cryptic Bemisia tabaci species. PCR amplifications for the mtCOI gene were performed using the Btab-Universal primer set for sequencing to determine if MED was of eastern (Israel) or western (Spain) origin. The cryptic Bemisisa tabaci species detected in the Dominican Republic in 2018 were MEAM1 (Middle East Asia Minor 1 or biotype B), MED (Eastern Mediterranean or biotype Q1) and NW (New World or biotype A). In 2018, 18 samples of 12 crops were collected in 11 provinces in the Dominican Republic: Azua, National District (2), Espaillat, Independencia, La Vega, Monseñor Nouel, San Juan (4), Santiago (2), Santo Domingo, Samaná and Peravia (3). In general, Cucurbita pepo (squash) was the most sampled plant (4), followed by two samples of Solanum melongena (eggplant), Phaseolus vulgaris (bean) and Cleome viscosa (tickweed). Other host plants sampled included Mentha spicata (mint), Solanum lycopersicum (tomato), Nicotiana tabacum (tobacco), Sesamum indicum (sesame), Chamaecyse hyssopifolia (spurge), Solanum torvum (turkey berry), Argemone mexicana (Mexican prickly poppy) and Citrullus lanatus (watermelon). MED were only detected in tomato in greenhouses in Pantoja-Los Alcarrizos, Santo Domingo (100% of the sample) and in tobacco mixed with weeds in Villa González (67% of the sample), Santiago. A single NW white fly mixed with MEAM1 was detected in eggplants in Espaillat and Santiago, and in poppy in the National District, where NW comprised 90% of the sample of 20. MEAM1 were the predominant cryptic species in all samples, regardless of the location or the host plant sampled.