First Record of Fungi Isolated from Thrips tabaci Lindeman on Garlic (Ilocos White) in Batac, Philippines

Abstract

The study aimed to isolate, and identify fungi associated with live adult female Thrips tabaci Lindeman (Thysanoptera: Thripidae) from garlic (Ilocos White) in Tubug Experimental Area of Mariano Marcos State University in Batac, Ilocos Norte, Philippines. Thrips were collected randomly from garlic (Ilocos White) plants within 200 m2 area in one garlic field of about 400 m2 using the tapping/beating method. Thrips were sorted and examined under the microscope. For the isolation of fungi, 20 live adult female thrips were selected from the collection consisting of females and larvae. Standard isolation of fungi from thrips was conducted and pure cultures of fungal isolates were maintained on PDA (potato dextrose agar) slants. Fungal isolates were processed for DNA extraction, PCR (polymerase chain reaction) amplification, and gel electrophoresis. Forward and reverse reads were paired to generate a consensus sequence, which was used in the Basic Local Alignment Search Tool (BLAST) queries to determine taxonomic identity. Out of the 10 fungal isolates, nine were identified as Fusarium proliferatum while one is Aspergillus candidus based on ITS (internal transcribed spacer) gene sequence. They both belong to Class Ascomycota. F. proliferatum on PDA shows varying characteristics of its mycelial growth from being scanty to fluffy, off-white to light yellow, brown, or purple while A. candidatus exhibits the entire margin and bluish-green pigmentation with a fertile layer composed of catenate conidia formed from the vesicle of the conidiophore. F. proliferatum was dominant among the isolates. The manner of isolating them from Thrips tabaci proved that they are endophytes living within them, and these are new records in the Philippines.