Slug and slater field trials
Slugs and slaters top the ‘most wanted’ list of truffle orchard pests, largely due to their wide distribution and, at times, very high numbers. They have been the focus of recent field work.
We assess the abundance of these nocturnal arthropods by placing bathroom tiles on the orchard flor and check them during the day. In order to fine tune monitoring for slugs and slaters we looked at the effect of location of tiles within an orchard – Where did we get optimum pest observations: next to the tree, between trees along the row or in the inter-row? This was conducted in two orchards in WA and two in NSW.
The results showed that in orchards with relatively minimal ground cover the slaters tended to congregate near trees. In orchards with more leaf litter and weeds/grass in the inter-row, slug and slater numbers were generally more evenly distributed, or with higher numbers found in the inter-row. This suggested that monitoring next to trees was the best option. Not only are you most likely to pick up pests with this placement but by placing the tiles next to trees is minimises disruption to orchard operations and makes it easier to mark their location for recovery and ongoing monitoring.
This variation in pest distribution across the orchard floor is not surprising given habitat preference of both slugs and slaters. Both prefer damp, dark places and feed on decaying organic matter. Where the orchard floor is relatively bare the area around tree trunks, particularly hazels with many suckers, is a more attractive habitat.
The next trial looked at the type of attractant placed under the tile. Previously we’d found that flaky bran increased the number of slugs under tiles compared to using no attractant. Alan Davey found that using dog kibble proved very attractive to slaters. We used flaky bran, dog kibble and cracked wheat as attractants under tiles to compare with tiles with no attractant. While overall slater numbers were lower than desirable for such a test there was nothing to suggest the other attractants were any better than flaky bran. Also we found that ants were attracted to the dog kibble. So we’re sticking with using the flaky bran under tiles for now as the recommended monitoring method
For orchardists who would like undertake their own monitoring, see the DIY article in this newsletter.
Current trials are looking at control methods for slugs and slaters. These trials are ongoing and results will be disseminated to growers at a later date.