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Beginner

Scientific Name: Glischrochilus species (Order: Coleoptera; Family: Nitidulidae)

Identification

• Most common sap beetles are picnic beetles
• Picnic beetles are about 6 mm in length, shiny, black in colour with four creamy-orange spots on their back.
• All sap beetles have short antennae with knobbed ends.
• Larvae are white, measure between 3 mm and 9 mm, have a brown head and 3 pairs of legs.

Often Confused With
Raspberry fruitworm
Japanese beetle

Period of Activity
The beetles become active as early as March or April, when they can be found close to their hibernation site (decaying plant matter). They move onto raspberries once fruit begin to ripen in July. Late-maturing varieties are more prone to sap beetle infestations because the beetles are most prominent in late summer and early fall.

Scouting Notes
Scout for beetles at harvest time. Look for ripe fruit with holes or other feeding damage and remove and destroy them as some may contain sap beetle eggs.

Thresholds
None established.

 

Advanced

Scientific Name: Glischrochilus species (Order: Coleoptera; Family: Nitidulidae)

Identification
There are several kinds of sap beetles that feed on overripe fruit. The most common are picnic beetles, which measure about 6 mm in length. They are shiny, black in colour with four creamy-orange spots on their back. All sap beetles have short antennae with knobbed ends.

The larvae are white, measure between 3 mm and 9 mm, have a brown head and 3 pairs of stubby legs.

The adult beetles are attracted to ripe raspberry fruit. They bore into ripe fruit to feed and lay eggs, making the fruit unsuitable for sale. Beetles that remain in the berries contaminate the harvested fruit. In addition, sap beetles can introduce bacterial and fungal diseases, causing fruit rot. Late-maturing varieties are more prone to sap beetle infestations because the beetles are most prominent in late summer and early fall.

Often Confused With

Raspberry Fruitworm
Both adult sap beetles and fruitworm larvae feed on ripe fruit, however, in the case of sap beetles, the holes may be larger and the presence of the bug more easily detected.

Japanese Beetle
Both Japanese beetles and sap beetles feed on ripe fruit, chewing large holes into the fruit and making it unsuitable for sale. Search for the presence of the beetles to determine which insect created the damage. However, in many cases, both beetle species will be present in a field at the same time.

Biology
This insect has one generation per year. The adult beetles can overwinter in various kinds of organic matter close to the soil surface. Once temperatures climb to 15 to 20°C, the adults become active and begin feeding. While berries are not yet ripe, they feed on sap, pollen and fungal mats. The beetles lay their eggs into decaying organic matter and early raspberry fruit. Larvae hatch and develop but then pupate in the soil. The new adults emerge in July and early August which coincides with the timing of population peaks.

Period of Activity
The beetles become active as early as March or April, when they can be found close to their hibernation site (decaying plant matter). They move onto raspberries once fruit begins to ripen in July. They are present throughout the harvest of raspberries.  

Scouting Notes
Scout for beetles at harvest time. Look for ripe fruit with holes or other feeding damage and remove and destroy them as some may contain sap beetle eggs. Sap beetles can also be found inside overripe fruit without any signs of feeding. 

Thresholds
None established.

Management Notes

• No chemical sprays give effective control of sap beetles.
• The pest can be managed by harvesting on a regular basis and removing damaged and diseased fruit as well as healthy fruit. Ripe, overripe and fermenting fruit serve as an especially powerful attractant to these beetles.
• Manage crop waste- especially melons, berries, corn. Bury or compost crop residue and discarded fruit, or locate at a different site.
• Never put boxes or flats of berries on the ground.
• Move harvested fruit to a screened building or shelter immediately after you pick.
• Baits may be used to trap beetles on a small scale. Apple cider vinegar or a mixture of yeast, sugar and water combined with a few drops of liquid detergent will drown the beetles.