Agriculture Reference
In-Depth Information
Adult cherry fruit flies resemble small houseflies, and the larvae are white
maggots that feed inside the cherries. The pest overwinters as pupae in the
top 4 inches of the soil. It emerges beginning about five weeks before har-
vest, and peak emergence is generally about harvest time. The adults spend
5 to 10 days feeding before laying eggs under the skins of the fruit. After
feeding inside the fruits, the larvae drop to the ground, tunnel in, and pupate
until the following year. The fruit flies usually remain very close to where
they emerge. Using effective control measures within an area will generally
reduce or eliminate the pest until it is reintroduced. An important control
measure is to eliminate all wild and escaped cherries in and around your
orchard.
To date, biological controls do not provide the perfect control needed for
commercial fruit. Yellow sticky traps and sticky red spheres can help monit-
or the pests, but results are poor to variable. According to Washington State
University, cherry fruit flies do not respond to attractant pheromones.
Early-maturing cherries are least susceptible to these pests. Pick all fruit
from the trees, as even a few remaining fruits can support a new generation
of flies. Harvest fruit as soon as it is ripe, and destroy dropped and culled
fruits. Surround provides some protection, and spinosad-impregnated baits
splattered in the trees have provided at least partial control of adults before
they can lay eggs. Spinosad also appears to be effective against spotted-
wing drosophila. At least two sprays are required, the first just as the fruits
are turning pink and the second 7 to 10 days later.
European Apple Sawfly
The European apple sawfly is an introduced pest that is now found in the
northeastern United States and Ontario. The adult flies are
⁄
4
to
⁄
3
inch
1
1
long with yellow heads, nearly black backs, and yellow to orange lower ab-
domens. They emerge from cocoons several inches below the soil surface at
just about apple bloom time. The females deposit their eggs in apple blos-
soms, and the resulting larvae feed near the surface on developing fruits,
causing prominent scars that make the fruit unmarketable. In later feeding,
