Assessing invertebrate damage to truffles at harvest and grading

Invertebrate pests can cause extensive damage to truffles. Much of this damage goes unseen, until harvest and grading by which time most of the perpetrators are no longer in or on the truffle.  While it can be difficult to differentiate between the feeding damage at this stage, some general feeding patterns can help narrow down the possible culprit.

Along with regular orchard monitoring, harvest damage assessments can help you to gain an understanding of the level of your invertebrate pest problem, the main causal agents and the impact of any management techniques undertaken.

Printable information posters are available in the links on the right for use in the field or grading room.

Truffle beetle

The most distinctive damage is that caused by the Australia truffle beetle (Thalycrodes sp. Family Nitidulidae).  Both the adults and the larvae are obligate truffle feeders. They make holes approximately 1mm in diameter and can tunnel extensively within a truffle.

truffle with pinhole damage [1]
Small pinhole damage typical of the Australian truffle beetle

Adults and larvae can be found in the tunnels even after harvest and washing.

Adult truffle beetles are very small, approximately 2-3mm long and 1-1.5mm wide. They are honey brown colour with distinctive clubbed antennae and rows of hairs on their back.

Australian truffle beetle larva adult [2]
Australian truffle beetle (below) compared to similar truffle infesting beetle (top). The smaller beetle is sometimes found in damaged or rotton truffle. It has no clubbed antennae and no rows of hairs on its back. 

Truffle beetle larvae are pointed at both ends, have a brown head, tiny legs on the thorax and a segmented body.

Australian truffle beetle larva [3]
Australian truffle beetle larva may be white or cream coloured

Invertebrates in the grading room

Other invertebrates that are not uncommonly found in and on truffles at harvest are springtails, pot worms, fly larvae and fungus gnats.

springtails on truffle [4]
Mutliple species of sprintails have been associated with truffles, some considerably smaller than those shown.
pot worm on truffle [5]
Pot worms can be found in truffles with some rot
fly larvae on rotten truffle [6]
Fly larvae on rotten truffle

These are thought to be secondary pests, meaning they only feed on truffle that is unsound. The truffle may have already had feeding damage or rot, developed cracks or been soft or over mature.

Holes and cavities

Slugs and slaters – produce deep and uneven cavities

Slug present in damaged truffle [7]
A slug actively feeding on a truffle
truffle with deep uneven cavity [8]
Damage typical of that caused by slugs and slaters

Black earwigs – produce uneven holes

an earwig on a truffle [9]
Black earwig feeding damage

Weevil larvae – produce holes approximately 5mm in diameter

weevil larvae protruding from a truffle [10]
Weevil larva are an uncommon pest of truffles

Millipedes – can produce uneven holes or browse the peridium

Portuguese millipedes feeding on truffle [11]
Many pests will eat both mature and immature truffle. Note the pale areas where the millipedes have browsed the peridium

African black beetle - adults produce holes approximately 10mm in diameter

An African black beetle protruding from a truffle [12]
African black beetles create larger holes in truffles

See Also

Australian truffle orchard - integrated pest and disease management [13]
Monitoring for invertebrate pests in truffle orchards [14]
Cultivation of black truffles in Western Australia [15]
Truffle orchard on-farm biosecurity and hygiene [16]

Documents

Truffle damage ID poster.pdf [17]
Australian truffle beetle damage ID sheet.pdf [18]

Links
[1] https://www.agric.wa.gov.au/sites/gateway/files/ATB%20damage.jpg
[2] https://www.agric.wa.gov.au/sites/gateway/files/styles/original/public/ATGB%20adult.jpg?itok=WssCc1QF
[3] https://www.agric.wa.gov.au/sites/gateway/files/TB%20larva.jpg
[4] https://www.agric.wa.gov.au/sites/gateway/files/springtails.jpg
[5] https://www.agric.wa.gov.au/sites/gateway/files/pot%20worms.jpg
[6] https://www.agric.wa.gov.au/sites/gateway/files/fly%20larva.jpg
[7] https://www.agric.wa.gov.au/sites/gateway/files/slug%20damage%202.jpg
[8] https://www.agric.wa.gov.au/sites/gateway/files/slug%20damage.jpg
[9] https://www.agric.wa.gov.au/sites/gateway/files/earwig.jpg
[10] https://www.agric.wa.gov.au/sites/gateway/files/weevil%20larva.jpg
[11] https://www.agric.wa.gov.au/sites/gateway/files/millipede%201.jpg
[12] https://www.agric.wa.gov.au/sites/gateway/files/ABB.jpg
[13] https://www.agric.wa.gov.au/new-horticulture-crops/australian-truffle-orchard-integrated-pest-and-disease-management
[14] https://www.agric.wa.gov.au/new-horticulture-crops/monitoring-invertebrate-pests-truffle-orchards
[15] https://www.agric.wa.gov.au/new-horticulture-crops/cultivation-black-truffles-western-australia
[16] https://www.agric.wa.gov.au/plant-biosecurity/truffle-orchard-farm-biosecurity-and-hygiene
[17] https://www.agric.wa.gov.au/sites/gateway/files/Truffle%20damage%20ID%20poster.pdf
[18] https://www.agric.wa.gov.au/sites/gateway/files/Australian%20truffle%20beetle%20damage%20ID%20sheet.pdf

Source URL: https://www.agric.wa.gov.au/new-horticulture-crops/assessing-invertebrate-damage-truffles-harvest-and-grading
This print version was generated at 4:22pm on the 18th of April, 2024.
The original document was last revised at Wed, 16/11/2022 - 9:42am

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Important disclaimer

The Chief Executive Officer of the Department of Primary Industries and Regional Development and the State of Western Australia accept no liability whatsoever by reason of negligence or otherwise arising from the use or release of this information or any part of it.