Host Plants and Distribution
Spittlebugs are found throughout North America and are pests of
strawberry plantings in areas of high relative humidity, such as the
Pacific Northwest. They are seldom a problem in the Canadian
Prairies. Spittlebugs feed on a variety of hosts, including
strawberry, clovers, grasses, weeds and some ornamentals.
Populations are higher in weedy fields and proper weed control can
keep numbers down.
Biology
Adult spittlebugs are 5-7 mm in length and are dull brown in
colour. Nymphs vary from white to pale green in colour and have dark
eyes and distinct legs. These insects overwinter as eggs on the
lower leaves and stems of host plants and in the stubble of
strawberry plantings. Egg hatch coincides with appearance of
blossoms. Nymphs feed within a frothy mass of spittle (hence the
common name), piercing plant tissue and sucking plant juices. The
nymphs are often found on and between clusters of flower buds and
within the crown. Nymphs mature in late June and emerge from the
spittle as winged adults. There is one generation per year.
Symptoms and Damage
In the Canadian Prairies, spittlebugs seldom cause economic
damage. Most often, they are a nuisance as pickers dislike the
appearance of the spittle. During wet summers or in fields under
heavy irrigation, numbers of spittlebugs may be high enough to
weaken plants and distort leaves and berries.
Scouting Techniques
Fields are easily monitored for the froth or spittle created by
the nymphs while feeding. During hot, dry weather, nymphs will be
lower on the plant, making them more difficult to locate.
Economic Thresholds
As spittlebugs seldom cause economic damage, there is no
established economic threshold. A threshold based on aesthetic
appearance of the plants to pickers is one froth mass per square
foot. Growers should strongly consider the impact of insecticides on
predators and parasites before controlling what is not an economic
problem.
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Spittlebug nymph on
strawberry bud
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