Tuesday, August 11, 2020

Combined Arms In The War On Aphids

Our cotton plants are suffering from an aphid infestation right now. My favorite solution is to buy a container of ladybugs and release them in the evening for a night of slaughter. This time, there was a nest of ants providing escort for the aphids, so my first wave of Coleopteran warriors was driven off with minimal casualties inflicted on the enemy.

The ants were reaching the aphid collections up the stems of the plants, so what I needed was some kind of barrier. I tried Vaseline, but it was a pain to apply. I bought a sticky glue designed to catch insects, but a closer reading of the label said it might harm the plant and extra work was required to use it safely. Finally, I took a chance and squirted corn oil on the stems.

Do you see any ants? Neither do I.

It turns out that corn oil is a cheap and easy barrier against ants. It doesn't last long - two days or so, but that should be enough for the ladybugs to do their work. I prefer to use corn oil in cooking as well as frying, so I keep it in both a condiment-sized squirt bottle and two-gallon jugs. It was super easy to apply. I just stuck my hand into the mass of plants and splorped away with the bottle.

Studying the ant problem, I discovered that ants don't like coffee grounds. Who knew? From now on, our morning coffee detritus will be dumped into the cotton's raised bed, mostly around the plant stems.

Yesterday, anticipating corn oil success, wife kitteh procured not one, but two containers of ladybugs. They were unleashed on our foes in the late afternoon. It isn't yet dawn, but when it's light, I'll examine the battlefield and see if we prevailed. 

On patrol.

Gathering for an assault.

My favorite photo of the bunch. A ladybug warrior in silhouette.


tim eisele said...

Seems like a sound, effective approach. The "insecticidal soaps" that you can find for sale are just vegetable oil with about 5% liquid dishwashing soap mixed in, it looks like you have demonstrated that the oil alone also works fine.

Where do you go to get lady beetles on short notice? Do garden supply stores in San Diego just routinely stock them? The only places I know of to get beneficial insects like that are through the mail (like https://www.arbico-organics.com/)

(speaking of which, I need to get some more BTI to suppress our mosquitos and black flies next spring)

K T Cat said...

Our local garden stores have them stacked up on the counter top at the checkouts. It's unusual if you don't see them.

The oil barriers on the stems lasted for about 18 hours, but the ants are now crossing them in small numbers. Several of the ladybugs have stuck around and are munching away. I'd estimate that the aphids took well over 50% casualties last night.

One or two more rounds ought to do it. In the meantime, coffee is being applied to the ground as well.

IlĂ­on said...

Often times in the fall, "nests" of ladybugs, or perhaps they are Asian lady beetles (in any event, they stink), invade my basement.

ligneus said...

Lady beetles is a new one on me, lady bugs is normal here, in England we call them ladybirds.

As for the oil, I use peanut oil, has a higher smoke point, is more expensive though, that's when I'm not using olive oil.