Last year, I was quite saddened and frustrated at having lost almost every fruit of my quince trees to brown rot, a common fungus that attacks stone fruits. However, it did not occur to me that more than a fungus was at play here. Today, after pruning unwanted growth from my 3-in-1 pear trees (which now almost exclusively produces quince), I discovered the telltale signs of insect involvement. I found a brown, crescent-shaped scar on the outside of one of the immature fruit and several others with tiny pinholes drilled into them.
After doing an Internet search, I found that the culprit is the plum curculio (AKA Conotrachelus nenuphar). This tiny weevil or snout beetle drills holes into the fruit (also apples, nectarines, pears, peaches, and plums), lays eggs, which turn to larvae. The larvae burrow toward the center of the fruit and leave nasty dark brown trails as evidence of their feeding. When the larvae are ready to enter the world, they exit the rotten fruit through the same hole that their mother made. The tiny holes drilled into the fruit make the fruit more susceptible to diseases like brown rot.
At least in my garden, I now know that these two culprits are working as partners in destroying my fruit. Several of the immature fruits look intact but I will be checking on them weekly, if not more often. Knowing the vulnerabilities in my garden will help me to be a better gardener and maybe enjoy some quince this year. I loathe the thought of cutting down my two trees, especially since they are still quite young, but I may if their problems spread to my apple trees.
An excellent series of photos of these brown trails and drill holes can be found here: http://www.thekitchn.com/quince-report-good-news-and-ba-65559
More information on the plum curculio beetle can be found here:http://entoweb.okstate.edu/ddd/insects/plumcurculio.htm
How To: Treatment of plum curculio for the home gardener is to just remove fallen fruit but I just would rather not give the larvae a chance to hit ground and have a chance to reproduce so I cut the fruit off the tree when I spot beetle damage and throw it away in the covered green-waste bin several yards away from the trees. More information on treatment can be found here: http://www2.ca.uky.edu/entomology/entfacts/ef202.asp
CONSUMER ALERT UPDATE: The quince is related to apples and pears, whose seeds are highly toxic if ingested. For this reason, do not ingest the seeds of these fruits.
More information on toxic plants can be found here:
Filed under: Gardening, How To, trees | Tagged: beetle, beetles, brown rot, Conotrachelus nenuphar, consumer alert, fruit, fruit tree, fruit trees, fruits, garden maintenance, Gardening, How To, insect abatement, insects, pear, pear tree, pear trees, pears, plum curculio, poisonous, quince, quince fruit crescent scar, quince fruit tiny holes, snout beetle, snout beetles, toxic plants, tree, trees, weevil, weevils | 1 Comment »