Strawberries are a favourite among home gardeners; unfortunately, this plant is also a favourite of garden pests. Many insects feed on the flowers of the strawberry plant, as well as on the juicy fruit. Root weevils, thrips and sap beetles all feed on the strawberry plant, causing damage and reducing the production of high quality fruit.
Several species of root weevils attack strawberries, feeding on the roots and crowns of the plant. Adult weevils damage strawberry plants, as well as the larval form. Adult root weevils are tiny, dark-coloured snout beetles that usually measure 1/4 inch in length. The larvae of this pest are white grub worms that are shaped like a C and measure 1/4 to 1/2 inch in length. Flower thrip feeding often causes strawberry plants to develop a dull colour. This pest is 1/16 inch in length and light brown or yellow and have wings. Nymphs are tiny wingless insects that are white when born, turning yellow as they age. The strawberry sap beetle is a particularly damaging pest of strawberries, causing tunnelling injuries in developing fruit. Adults are oval-shaped beetles that measure 1/8 inch in length. The larvae are white, wormlike pests that have a brown head capsule.
Root weevils feed on strawberry roots in their larvae form. Plants often develop severe tunnelling injuries from root weevil infestations. Adult forms of this pest often feed on plant leaves, placing notches in the leaves. Strawberry plants with heavy infestations of root weevils can be stunted or die. Plants with flower thrip infestations often have dull coloured fruit that is very seedy. Fruit fails to mature and fruits are smaller when thrips are present and actively feeding on strawberries. Heavy infestations of flower thrips make strawberries unfit for sale. Strawberry sap beetle feeding often causes deep tunnels in fruit and increases the risk of fruit rot.
Keep your strawberry plants healthy and stress free to prevent infestations of insects. Many pests are drawn to overripe fruit, so avoid leaving ripe fruit on your plants. A number of predatory insects feed on root weevils, thrips and sap beetles, keeping them under control. Parasitic wasps lay eggs in adult beetles.
Insecticides are available at your local garden centre for pest control on your strawberries. These products work best when combined with cultural control methods. Be sure to adhere to all label instructions regarding the use of insecticides and harvesting fruit. Post harvest sprays often help control insects prior to egg laying.