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Each week, 10 leaves are taken from the lower and upper canopy of 10 trees in each plot for a total of about 100 leaves. Samples are run through a brushing machine and the insects that fall off are counted. In spring, the focus is on fruit spur leaves, where the first psylla nymphs are concentrated. In summer, both spur leaves and new shoots are sampled.
30 limbs are sampled with a beat tray at each plot. Psylla adults and natural enemies are counted. Natural enemies include: predatory bugs (Deraeocoris, Campylomma, minute pirate bugs, damsel bugs, big-eyed bugs), Trechnites wasps, earwigs, lacewings, ladybeetles, and spiders.
There are two types of sticky card traps at each plot which collect flying adult insects. Each trap has 4 replicates.
1) Green lacewing, Chrysoperla plorabunda species (yellow card with AMP lure).
2) Green lacewing, Chrysopa nigricornis species (white card with squalene lure).
Trechnites wasps found on yellow sticky cards are also counted.
The graph below shows the sum of all natural enemies caught on sticky cards. This would include adults of both species of green lacewing, Campylomma bugs, Trechnites wasps, brown lacewings, Deraeocoris bugs, and ladybeetles.
The graph below shows the average number of Trechnites wasps collected from four yellow sticky cards.
This work is supported by a grant from the National Institute of Food and Agriculture (2019-70006-30443).