By: Dr. M.O. Way, Prof. of Entomology, Texas AgriLife Research & Extension Ctr.
For this article, I want to talk about the South American rice miner, Hydrellia wirthi, which I observed last week infesting fields of Cheniere and XL753 near Nome, TX. This species is exotic and originated in its namesake. I first observed this insect feeding on rice in fields west of Houston in 2004/2005. This is a minor and miner pest (a little joke there…very little!). Around this time, it was found in Louisiana attacking a field of seedling rice. In this case, the farmer had to replant. The adult fly lays an egg on rice foliage near the junction of the leaf sheath and blade. The egg hatches and the larva bores into the leaf and begins feeding. It continues mining the leaf until it pupates and emerges as an adult fly. The signs of damage are tattered, ragged leaves. Sometimes the larva will mine the leaf when it is furled; when the leaf “unfurls”, the damage is something like when you made a snowflake as a kid. You would fold up a piece of paper, then cut random holes in the edges, then when you unfolded the paper a snowflake appeared! With this insect, when the damaged leaf unfurls, the damage runs up and down and across the leaf. Often the end of the leaf drops off leaving yellowish mines or stripes running up and down the leaf. Sometimes the end of the damaged leaf will hang onto the rest of the leaf by a small piece of leaf tissue. So, the plant takes on a ragged appearance. Damage I have observed in Texas has always been minor (there we go again!) usually after flood when rice is tillering. It takes a lot of defoliation at this time (about 20%) to affect yield. Also, I have most often observed damage where stands are low next to levees or water boxes. Go to the following LSU AgCenter link to learn more about this insect https://www.lsuagcenter.com/topics/crops/rice/insects/presentations/16south-american-rice-miner.
So, if you see this type of damage, don’t be alarmed unless the damage is really bad throughout the field. You can always contact me at 409-239-4265 or firstname.lastname@example.org.
I also want to make you aware of the Beaumont Center Virtual Field Day. You can access the videos of our scientists giving talks on their 2020 research by clicking on this link https://beaumont.tamu.edu/RiceFieldDay/?fbclid=IwAR04VrNpcECHPv1bp6Gl3hzN_i97E1TMOYt4ydfMYBVEVE51_I3_mNgV5yU.
Ok…all for now! Stay safe and healthy!