Results from trap trials using a male cricket call to lure in females are promising, with the new tool capturing more than 100 female crickets during a 24-hour period.
The work is part of the Vegetables NZ-A Lighter Touch project, being undertaken by Bioeconomy Science Institute (BSI) at a kūmara farm near Dargaville.
Cricket on nearby maize crop. Credit: BSI
The project team is analysing the data collected from trials over 16 nights (5pm to 9am) and 14 days (24 hours) during the cricket season. The black field cricket Teleogryllus commodus is a damaging pest of vegetable crops and pasture in northern New Zealand with few control options for growers.
BSI scientist and project lead Sophie Hunt initially deployed traps at night using both acoustic caller and light to attract crickets. However, after observing crickets also using the traps as daytime refuge, she expanded monitoring to compare day versus night catches, and ultimately shifted to 24-hour sampling.
Crickets caught in the trap during the day. Credit: BSI
Night trials compared four trap treatments: a control trap, a trap with an acoustic caller, a trap with a light source, and a trap combining both the light and caller. The combination of light and caller performed the best, averaging five adult females and 1-2 adult males caught, per trap, per night.
In the 24-hour monitoring using the caller only, traps averaged 20 female adult crickets were caught and 1-2 adult males per trap. Sophie notes that these averages included nights affected by low temperatures or rainfall, which reduced trap efficiency, while in favourable conditions individual traps sometimes captured more than 100 females in a 24-hour period.
A range of trap types were tested, and a prototype trap was developed before the field trials with a one-way door to target crawling crickets. Once the trap design is finalised, it will be available to growers as open source technology, able to be constructed with a combination of commercially available plastic containers and 3D printed components.
The trap prototype used in the trials. Credit: BSI
Next steps for the project are to start evaluating bioinsecticides to use with the trap. The aim is to capture the crickets and then infect them with a bioinsecticide, killing them and therefore reducing the risk of the crickets’ damaging crops. A wild colony of crickets has been established by BSI, and these crickets will be used in the bioinsecticide evaluation work.
Marking crickets for mark, release and recapture trial. Credit: BSI
All life stages of the cricket feed on kūmara tubers underground, resulting in damage which can lead to crop losses of $10,000 to $30,000 per hectare depending on market pricing. While complete crop loss is rare, in some cases entire fields can be rendered worthless due to feeding damage.
Learn more about the project here.
