Blackberry Mite
Acalitus essigi Hassan
This mite attacks blackberries and raspberries and frequently appears in orchards in Croatia.
Affected Part: Fruit
Description of the Pest: Adult mites are worm-like and translucent white. They have two pairs of legs and are very small.
Biology and Life Cycle of the Pest: Adult mites overwinter under the bud scales but can also be found on residual fruits on the plants. In early spring, they move to the leaves, and during flowering, they enter the flowers and then the fruit.
Damage Caused by the Pest: Fruits ripen unevenly, are irregularly colored, hard, and tasteless. They cause more damage to late-ripening blackberry varieties.
Protection Against Blackberry Mite: Damage can be reduced by proper pruning and applying sulfur-based preparations in the spring. The need for control measures is determined based on the intensity of the previous year’s infestation.
Raspberry Cane Midge
Resseliella theobaldi Barnes
This pest occasionally causes significant damage in raspberry and blackberry orchards.
Affected Part: Shoots
Description of the Pest: Adults grow from 2 to 2.5 mm in length and are ocher-red. Males are smaller than females. The eggs are whitish. The larvae are small, up to 3 mm long, and reddish. The pupae are reddish and found in cocoons.
Biology and Life Cycle of the Pest: The larvae overwinter in cocoons in the soil. Adults appear in April and lay eggs in longitudinal cracks in young shoots. The eggs hatch in 5 to 8 days, and the larvae feed on the shoot tissue. Purple zones appear around the affected areas. At the end of development, the healthy larvae leave the shoots, burrow into the soil, spin cocoons, and pupate. The development from egg to adult takes about 40 to 60 days. There are three generations per year.
Damage Caused by the Pest: Affected shoots dry out. The pest also facilitates the entry of various fungi under the bark, especially Didymella applanata and fungi from the genera Fusarium, Verticillium, and Coniothyrium, which significantly increase the damage.
Protection Against Raspberry Cane Midge: Since the raspberry cane midge overwinters in the soil, tilling around the plants reduces the number of overwintering pupae.
Raspberry Crown Borer
Coroebus rubi L.
This pest is found in the wild on roses and blackberries.
Affected Part: Leaves and shoots
Description of the Pest: Adult beetles grow from 8 to 11 mm long and are purple-black. The larvae are dirty white and grow up to 30 mm long.
Biology and Life Cycle of the Pest: The larvae overwinter in the root collar or roots. After overwintering, they move upwards and pupate in the shoot. Development takes about two weeks. Adults emerge in May and begin feeding on the leaves. After feeding, the female lays eggs on the shoots. The larvae develop from the eggs.
Damage Caused by the Pest: Damage becomes apparent in spring after the larvae have overwintered in the shoot. The larvae bore a tunnel downward in the shoot. Infected shoots do not leaf out and break easily. Severe infestations can destroy up to 90% of fruiting shoots.
Protection Against Raspberry Crown Borer: This pest can be controlled by cutting and burning the infested shoots, ensuring that the part containing the pest is removed. During winter, it is necessary to dig up the infected root collar and cut and burn the infested shoots. Using healthy planting material is a preventive measure to avoid introducing the pest into the orchard. Wild roses and blackberries around the orchard should be destroyed.
Raspberry Beetle
Byturus tomentosus Fabr.
This pest, besides attacking raspberries, also affects blackberries.
Affected Part: Flower buds, flowers, and fruit
Description of the Pest: Adult beetles have light brown bodies covered with grayish hairs. The body is elongated and oval, growing from 3.5 to 4 mm long. The antennae consist of 11 segments. The eggs are elongated-elliptical, white or yellowish, and about 1 mm long. The larvae are brown and covered with yellowish hairs, growing up to 8 mm long. They have three small thoracic legs. The head is well-defined and dark-colored. The pupae are white and 3.5 to 4 mm long.
Biology and Life Cycle of the Pest: The adult form overwinters, usually in the soil. They become active and reappear in late April and May, feeding on flower buds and flowers. Females lay eggs in flower buds and later in the fruit. Each female lays 80 to 100 eggs. The larvae develop from the eggs in 8 to 10 days and feed within the fruit. The larval stage lasts about a month and a half. In warm and dry conditions, adults are more active, causing more damage and laying more eggs, but high temperatures and low humidity negatively affect embryonic development. There is one generation per year.
Damage Caused by the Pest: Adults destroy flower buds and flowers by gnawing them. Laying eggs in the buds causes them to dry out. The larvae damage the fruit as they develop and feed inside it. The pest particularly attacks early raspberry varieties.
Protection Against Raspberry Beetle: The raspberry beetle can be controlled in winter by digging around the raspberries, as it overwinters in the soil. Insecticides based on fosalone and endosulfan can be used before flowering and oviposition, when the pest starts causing damage to the buds. White sticky traps are used to detect and monitor the presence of this pest.
Rose Leafhopper
Typhlocyba rosae L.
This pest can also severely damage raspberries and blackberries. It is a highly polyphagous insect.
Affected Part: Leaves and shoots
Description of the Pest: The adult is 3 to 3.5 mm long. Its body is greenish-yellow, narrow, and elongated, with a noticeably broad head. The larvae are creamy in color.
Biology and Life Cycle of the Pest: The eggs overwinter under the host’s bark. In early spring, the larvae hatch and move to the leaves, where they suck the sap. Their development takes about 30 days. In late May and June, the adults of the first generation appear. They live for a relatively long time—up to two months. They lay eggs on the leaves, from which a more numerous second generation develops, causing the most damage. The adults of the second generation appear in September, and in coastal areas, they can be found until November. They lay eggs that overwinter.
Damage Caused by the Pest: Initially, small whitish spots appear on the leaves where the insect feeds, eventually merging to cover the entire leaf, which then turns pale (dechlorophyllation) and begins to curl. On the underside, numerous shed skins and live insects can be observed. The pest also causes damage by laying eggs in the shoots, which then become stunted. The damage is particularly severe in enclosed spaces where there are no natural predators.
Protection Against Rose Leafhopper: Cutting infested shoots in winter helps reduce the damage. Winter spraying destroys the eggs, using oil-based organophosphorus insecticides. The action threshold is considered to be more than 50 pests per 100 leaves. Natural enemies serve as a biological control measure.
Less Significant Pests of Blackberries
Other less significant pests of blackberries include:
- Raspberry Leaf Midge (Dasyneura plicatrix H. Lw.)
- Raspberry Leaf Roller (Incurvaria rubiella Bjerk.)
- Raspberry Moth (Notocelia uddmanniana L.)
- Raspberry Clearwing (Pennisetia hylaeiformis Lasp.)
- Two-Spotted Spider Mite (Tetranychus urticae Koch.)
