Answer: It sounds like the damage is caused by the tarnished plant bug (TPB). The wingless yellow or tan nymphs are 1/8 inch long and somewhat resemble aphids; adults are about 1/4-inch long and 1/8-inch wide, flattened and oval in shape; wings are folded flat over the body. Both the nymphs and adult insects feed by piercing the plant and sucking out sap, at the same time injecting a toxin into the plant tissue.
On strawberries, the insects usually feed on a cluster of seeds on one area of the berry; these seeds abort and stop producing growth hormones, so the tissues surrounding the area ceases to grow. Severe deformation is commonly referred to as "buttoning" or "catfacing" -- the hard, seedy tips you describe.
Tarnished plant bugs are found throughout the country and attack a variety of vegetable, fruit, forage, and flower crops, as well as a number of weeds. Among fruits, it attacks not only strawberries but also apple, peach, pear, and most other deciduous and small fruits.
TPB is difficult to control because the insects have many different plant hosts and many generations a year. Good garden sanitation is the first line of defense. Keep weeds controlled in the strawberry beds and around the garden where tarnished plant bugs may be hiding. Most of the damage to spring-bearing strawberries is done between petal fall and young berry formation. However, for best control, reduce the population of tarnished plant bugs before petal fall. Begin checking the flower buds and foliage for nymphs weekly, starting when flower buds are first evident. If you spot nymphs, spray with insecticidal soap, being sure to cover the undersides of the leaves completely.
Attracting beneficial insects to your garden may help in controlling the pest.
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