Applied Entomology and Zoology (2015) 50, 245-254

Kaori Tsurui, Tsuyoshi Ohishi, Norikuni Kumano, Kiyohito Teruya, Tetsuya Toyosato and Keiko Shiromoto (2015)
Symptoms shown by late-stage larvae of the West Indian sweet potato weevil Euscepes postfasciatus (Coleoptera: Curculionidae) infected with Farinocystis sp. (Neogregarinida: Lipotrophidae)
Applied Entomology and Zoology 50 (2), 245-254
Abstract: Pathogen outbreaks often represent a major issue when mass rearing target insects for biological control, even when applying sterile insect techniques (SIT). Here, we aimed to improve existing screening techniques used to detect a neogregarine Farinocystis sp. that infects the West Indian sweet potato weevil Euscepes postfasciatus Fairmaire (Coleoptera: Curculionidae) mass reared under the SIT program. Our results revealed that infected late-instar larvae exhibited swelling symptoms, and that their body weight and head width significantly increased compared to uninfected larvae. The head width to body weight ratio differed between infected and uninfected larvae; yet, head width was highly correlated with body weight in both cases. Visual diagnosis based on the appearance of the late-instar larvae showed concordance of almost 90 % with the current diagnostic methods of optical microscopy and PCR. Thus, the swelling symptoms observed in late-instar larvae were directly noticeable. Therefore, visual diagnosis, based on larval appearance, represents a feasible, low-cost technique for the early detection of Farinocystis sp. infection of the West Indian sweet potato weevil.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Kaori Tsurui, Norikuni Kumano

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
rearing/culturing/mass production
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Euscepes postfasciatus		Japan
Farinocystis (genus - entomopathogens)	Euscepes postfasciatus		Japan