Consperse stink bug
-- Christian Krupke
There are more than 200 species of stink bugs in North America. Adults are usually some shade of green, tan, or gray-brown. Many feed on plants, but a few are predaceous (see rough plant bugs Brochymena sp. in Other Predatory Bugs). The two most common stink bugs in apple and pear orchards are the consperse stink bug and the green stink bug. The redshouldered stink bug (Thyanta accerra), Say stink bug (Chlorochroa sayi) and the onespotted stink bug (Euschistus variolarius) will also attack tree fruits.
It is uncertain whether or not nymphs of stink bugs can survive on tree fruits. Observations indicate that although eggs are laid and will hatch, the nymphs do not survive for any length of time. The primary concern is for adults migrating in from herbaceous hosts and feeding during either late spring or close to fruit harvest. Damage has been observed on apple, pear, cherry, peach, apricot and plum.
Egg: The egg is barrel shaped. It is pearly white at first but turns pink. On top of each egg is a circle of white projections. Eggs are laid in clusters.
Nymph: The nymph develops through five instars. The color of young nymphs can vary from black to white with reddish markings. Older nymphs have yellow and brown bodies with black markings.
Adult: The adult is shield-shaped and about 1/2 inch (12 mm) long. It is pale brown with small black specks on the back, yellow beneath, and red antennae. The black specks help distinguish it from the predaceous Brochymena stink bug species, which are gray with white specks.
Consperse stink bug adult (J. Brunner)
Stink bug eggs and nymphs (H. Riedl)
Green stink bug:
Green stink bug adult (J. Brunner)
Egg: The egg is barrel shaped. Eggs are laid in clusters of about 30 to 40 on the undersides of leaves.
Nymph: The color of the nymph varies from instar to instar and from individual to individual. Young nymphs are generally dark with red or orange markings. Older nymphs are mostly green, with orange markings at the edge of the thorax and abdomen and several large black disks down the center of the upper surface of the abdomen. The first instar is 1/25 to 1/17 inch (1 to 1.5 mm) long, and the fifth instar is 2/5 to 1/2 inch (10 to 13 mm) long.
Adult: The adult is 1/2 to 3/4 inch (14 to 18 mm) long and is a bright green. It has inconspicuous yellow-orange and black markings along the lateral edge of the abdomen. The lateral margins of the head and thorax are yellowish.
Adults often migrate to orchards in late summer from surrounding areas in search of moisture when uncultivated vegetation starts to dry. Trees in outside rows are likely to be the most severely damaged. Eggs for the second generation are usually laid on broadleaf plants in the cover crop. There are 2 or 3 overlapping generations each season. Adults seek overwintering sites in October or before fall frosts.
Stink bug damage to Golden Delicious apple (E. Beers)
Peaches: Feeding of adults causes cat-facing or dimpling on fruit. If fruit is almost mature when injured, the flesh does not turn corky but begins to decay. Damage on peaches is more noticeable than on apples or pears.
Cherries: Early season feeding causes cat-facing, dimpling and deformity. Feeding later in the year discolors the flesh around the pit. Because the damage is not visible from the outside, cherries with this type of injury are generally not sorted out during packing.
Stink bug damage to sweet cherry (T. Anthon)