Polymorphisms in entomopathogenic fusaria based on inter simple sequence repeats

Isolates of Fusarium obtained from Dactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae) demonstrated potential as biological control agents against that same insect, which is a pest on Opuntia ficus-indica L Miller. The isolates belong to two species complexes: Fusarium incarnatum-equiseti (FIESC - five species) and Fusarium fujikuroi (FFSC - one species). Twenty-eight isolates of these fungi were characterised using seven Inter Simple Sequence Repeats (ISSR) primers. The UBC841 primer differentiated all the FIESC isolates studied and the single isolate of Fusarium pseudocircinatum O'Donnell & Nirenberg at a level greater than 90% similarity for the fragment sizes. The results indicated high genetic variability among those isolates, an important characteristic for biological control, increasing the chances of finding efficient fungi for insect control. The ISSR markers UBC834 and UBC841 were found to be efficient for characterising and differentiating (DNA fingerprinting) those fungi, and could be used in field monitoring.