By Guy K. Ames, NCAT Horticulture Specialist
Sure, that’s a strange title for my blog, but I can explain: I have two, somewhat distinct, important points to make here.
This morning before heading for the office, I took one of my usual walks to enjoy the cool morning temperatures and to see whatever new, beautiful, blooming thing Mother Nature had unveiled overnight. A slight detour from my usual route took me close to my elderberry patch which even my first cursory glance told me wasn’t right. Wow. A closer look revealed that the patch had been stripped of most of its foliage! See photo 1.
I had been working in the vicinity just last week and was stunned by the sudden nude aspect of the plants. A still closer look revealed the culprits: hundreds, thousands of squirming, translucent green larvae that I did not immediately recognize. See photo 2.
Identifying the Attackers
Not having encountered this pest before but knowing that I needed to do something quickly, I relied on past experience and considerable entomology education. I asked my son to mix up and apply some Bacillus thuringiensis (B.t.), a bacterial and organic pesticide specific to lepidopteran (moths and butterflies) larvae.
In the meantime, I got on the internet and went to the University of Missouri’s Center for Agroforestry’s elderberry growing guide, my go-to for everything elderberry. I quickly discovered that what I was dealing with was not a lepidopteran but, rather, the larvae of the elderberry sawfly, a pest notorious for just this kind of almost-overnight damage. This was pivotally important: If we had relied on B.t. for controlling this pest, we would’ve been very disappointed! B.t. would probably have been completely ineffective for controlling this dipteran (flies, gnats, and mosquitoes) pest. I called my son on his cell and asked him to scratch the B.t. and, instead, mix up and apply Venerate™ (https://marronebioinnovations.com/ag-products/brand/venerate/), a new bioinsecticide approved as “organic” and which does have insecticidal activity against chewing, larval dipterans like the elderberry sawfly. Whew! Now, off to the office!
Okay, here are the two important points I want to make:
- An old homily says, “A farmer’s footsteps is the best fertilizer.” And I often edit that a little to say that “A farmer’s footsteps is the best pest control.” That, of course, is a poetic way of saying that a farm benefits from the farmer’s attention. Get out there and look at your plants and your livestock. Every day.
- Proper I.D.! I very nearly wasted my and my son’s time and money by almost applying a pesticide that probably would have been ineffective. I’ve been at this a long time, and Mother Nature continues to fool me with curve balls! It’s good to remain humble and look it up! Proper identification can even prevent you from accidentally spraying a beneficial insect.
Guy has produced several insect pest identification sheets for fruit trees. Find them in the ATTRA Sustainable Agriculture website’s horticultural crops section. Guy and NCAT’s other agriculture specialists are here to answer your questions about pest management, production, marketing, and much more. Call our helpline at 1-800-346-9140 or email firstname.lastname@example.org.
About the Author
Guy K. Ames is a Horticulture Specialist with NCAT and its ATTRA Sustainable Agriculture Program. He has over 40 years of experience gardening, farming, and orcharding. Guy has a B.A. in history from Texas A&M, Commerce and an M.S. in horticulture (fruit crops and pest control in fruit crops) from the University of Arkansas, Fayetteville. Guy has operated Ames Orchard & Nursery since 1983.