To what purpose ....?

Al

Hey, Al! A shift from the Container forum! Good to see you.

This is the third year I've been working on an organic solution to cucumber beetle control in the garden, along with a few people on the Vegetable forum, though most seem to have disappeared this year. So I'm carrying on pretty much alone.

Anyway, the link at the bottom describes various ways of attracting cucumber beetles (and only cucumber beetles) to a couple of lethal brews that end their lives. Among the many possibilities is a spray mixture of Buffalo Gourd root powder and Red Dye #28 so that its dispersal looks a bit like the picture at the top, though that picture is the red dye and a bitter melon juice. The only reasonable price I could find for Red Dye #28 was in dental "disclosure tablets", the ones you chew so the plaque in your mouth will show up. Some of the brands use Red Dye #40, which apparently does not have the same lethal effect on cucumber beetles. So I've ordered some that use the #28.

I also ordered some Buffalo Gourd seeds to see if I can grow them and use the ground-up roots next year as the lure. They are considered to be an invasive pest in the west, and the roots can get huge, up to 66 pounds has been reported. So my growing this year will have to been in the largest trash can I can find to keep it under control. If that doesn't work, there are other lures that work fine, some of which I already have. But Buffalo Gourd has a bonus, mentioned below.

In years past, this very informal group of GW people used clove oil (attracts only female cuke beetles) and tayuya root (South American gourd/melon mentioned in the article) powder bought through the internet. Two other excellent lures are Caserta squash (apparently no seeds available anywhere this year), and Buffalo Gourd fruits and roots. Buffalo Gourd has the added bonus of reputedly being a squash bug repeller, so the spray-on concoction might work to keep cucurbit patches free of both pests!

The last two years we used tayuya or clove oil mixed with Sevin placed in cups on trellises or around the patch. They actually work very well, though like all insecticides, there are always more insect pests than ways to control them. After a week or ten days, I have been unable to find any cuke beetles except occasionally on my plants. And the garden is right next to a corn field where they flourish. Three years ago the garden was overrun by them.

But I hate those cups in the garden that have to be collected every fall. And because they were open-topped, when it rained the cups filled up and overflowed, polluting the garden (Sevin takes a couple of months to become non-toxic) and becoming utterly useless, too.

So I'm looking for an expansion of the principles discussed in that link for home gardeners to use. If the disclosing tablets work by providing enough of the #28 dye to be phototoxic to the beetles, I won't have to use Sevin anymore. If I can concoct a spray that clings to the leaves but doesn't suffocate the plant, that would be great! If not, I thought I might put the dye-lure mixture into scooped out cucumber boats in the cucurbit patch and just let them do their work and eventually disintegrate there -- no poison in the soil.

More than you wanted to know, huh?

Anyway, this question is about how to get the lure and dye to stay on plant-leaves without harm long enough for the beetles to find them and feast away before it's washed off by rain.

Don't laugh, but I even thought of a very thinned solution of plain cooking gelatine as the lure-dye base! But I think that would not allow leaf-pores sufficient respiration unless it were sprayed extremely thinly on the surfaces.

Here is a link that might be useful: Cucumber Beetles, the Bitter End

That is interesting. Attracting bugs to kill them has become an art form.

Is anyone spraying the plants with either seaweed, milk, or molasses? The idea with these is to improve the health of the microbes living on the surface of the plant so they can help repel the beetles.

Another thought is to put a bird bath and bird house in your garden to attract beetle predators.

dchall_san_antonio

Not much can "repel" cucumber beetles -- they can and do take down the healthiest of plants. And birds won't eat cucumber beetles because of their bitter bitter taste.

I'm still hoping to find a safe simple spray base, not a nutrient or anti-fungal or something that might mask the odor of the lure but just something that will hold the lure and dye on the leaves long enough for the beetles to partake of it for a few days after each spraying.

There is no "adhesive" made that would stick to a plants leaves that long and not kill the plant it was trying to protect. Anything you put on a plants leaves that will prevent that leaf from doing what is is supposed to do, transpire moisture as well as utilize the sunlight to make nutrients will cause that leaf to die.
There is also no known adhesive that you could put on something else that would remain sticky long enough to trap an insect that the rain would not wash off.

kimmsr

I'm not looking for something sticky to trap insects. They don't need to be trapped, just attracted to the spray on the leaves, which is accomplished by the lure in the spray. I just want something that will temporarily provide thin droplets that is not harmful to the leaves that can be washed off by rain or water.

It isn't true that there is NOTHING that will accomplish this since there are many sprays used on plant leaves that don't kill the plants. I just don't need those that have fungicides or insecticides in them.

Well, maybe I'll have to devise something myself. I probably haven't described the process or what's needed very well.

Thanks, all!

Anney,
I understand what you are looking for. This isn't my area of expertise but find it interesting so will be watching for updates on your progress. Please don't let nay sayers deter you. I don't have problems with the cukes beetles but who knows when it may start. JD

Anney, a few thoughts after a close reading of the article written in 1999. I am unable to find any updates on the method described. To address your specific question:

1. It appears that 'timing' is critical to this technique. The beetles must be actively feeding. When this is observed the spray must be applied at the right time, probably very early morning to discourage evaporation of droplets on the leaves. I can think of no way to encourage a water droplet to retain its shape and stay liquid for hours. You certainly could run some experiments on a shrub to see if you can figure out a method. Try adding a drop or two of glycerine to 4 cups of water to see if that helps and does no harm to foliage. Interesting question.

2. Perhaps the normal method of adding one drop of a surfactant to four cups of water/spray mix (I use lemon detergent with no additives or Method, Go Naked dishwashing soap) is still the best way to ensure an even coating of thin droplets on a leaf.

nandina

Yes, you have to spray or use the traps when they're feeding, so you need to be aware of when they first come calling and when they're most active once they've arrived. I've read it's May-June-July after temps get steady at 65 and above. I've seen them feeding at all times of the day, but for spraying, I think you're right that the morning would probably be the best time to do it since they're likely to be hungrier soon after the sun comes up.

I did some research on glycerine and though it initially sounds like it would be something to try, the site at the bottom claims that glycerine spills (overturned trucks of it, etc.) are toxic to humans, animals, and plants, so I assume it wouldn't be a good thing to spray on cucurbits.

A liquid detergent with no additives to hold the lure and dye in suspension is something I can certainly try. It would be great if it works.

This project is not nearly as complicated if you just mix the lure and the dye and soak cucumber boats in it and place it in the garden among the plants! But the spray might work better for trellised cucurbits, so might as well apply myself to it as well.

Thanks for the suggestions, nandina.

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And elkwc, the process is so near success now that I'll certainly complete the testing. Thanks for the encouragement. Someone who's a small seed vendor is interested in it, too, though it's for her own garden and maybe to suggest some of the seeds she sells might be good lures for people who want to grow cucumber beetle trap crops. She said she finally gave up trying to grow squash after three plantings in a row were destroyed by them. They are really terribly destructive if you live in areas where they are.

Here is a link that might be useful: Risk Management for Toxic Chemicals

I thought you were trying to get rid of the bugs. I see now you are simply trying to prove a point.

I am picturing something like the sugar drops that are not supposed to ooze out of meringue but we've all seen them. Seems to me there are carnivorous plants that secrete sticky drops in order to capture insects. Flypaper plant? Sundew? Is this what you have in mind?

I am picturing something like the sugar drops that are not supposed to ooze out of meringue but we've all seen them. Seems to me there are carnivorous plants that secrete sticky drops in order to capture insects. Flypaper plant? Sundew? Is this what you have in mind?

No, as I said above: I'm not looking for something sticky to trap insects. They don't need to be trapped, just attracted to the spray on the leaves, which is accomplished by the lure in the spray. I just want something that will temporarily provide thin droplets that is not harmful to the leaves that can be washed off by rain or water.

I don't know how I can make it clearer, and I have no idea what point you think somebody's trying to prove. I'm just trying to get ideas for a liquid that I can use to temporarily suspend a lure and some dye in that won't damage plant leaves and won't change the character of the lure or the dye.

What form of bait are you planning to use? Are you planning to juice the melon, or dry the root and reconstitute it?

So you have a pesticide (phloxine B, aka 'Red Dye #28') which will kill the critters, you have a bait (root or melon juice) which will attract them, and you need a carrier to apply and hopefully keep it liquid form for an extended period so that the targeted insects can find and ingest it.

Are you concerned that water will evaporate too quickly on its own? Glycerin is hydroscopic, so it might help. It is pretty benign from an environmental standpoint and not particularly hazardous in the concentrations/amounts you'd be using. You can see the information in the MSDS for glycerol (below).

If you are using the melon juice, it probably has some sugars (fructose is hydroscopic) in it - it might be good all on its own depending on the concentrations.

I wonder about the effectiveness of soaps - it might put off the taste of the solution and render the bait ineffective.

It sounds like a fun little project. Good luck.

Here is a link that might be useful: Glycerol MSDS

pferrell

Yes, a carrier for the spray that will stay on leaves long enough for the concoction to be ingested by cucumber beetles! Succinct!

Water might last long enough if the lure/dye is sprayed into the leaf axils or anywhere else it might pool. But plain water evaporates pretty quickly from leaves and I think it would probably drip right off many leaves into the soil! That wouldn't harm anything but then the beetles would probably not be interested in it if it were in the soil, even if it remained on top.

For the spray, the lure will be either tayuya root powder (available through the internet) or some form of Buffalo Gourd root or fruit, maybe a slurry or a dried powder, though I think a fine sprayable slurry of the fresh parts of the plant would be a better lure.

Caserta squash fruits and plants are also extremely attractive to cuke beetles, but I can't find those seeds anywhere this year -- everybody says "not available". It was an AAS selection one year because the fruits are good and the plant is sturdy, but I'll bet nobody wants to grow it because it's so attractive to cucumber beetles.

The researchers don't say what that mutant bitter watermelon actually is, and I haven't seen anything like that description for sale anywhere. Maybe the sugars in it make the juice a good clinging agent on leaves, and I'm led back to my idea that maybe sugar mixed with the liquid in the lure and dye would do the trick.

The glycerol is still iffy to my thinking, though I see that it isn't considered to be an environmental or human hazard except in large quantities. If I can't find something in my pantry, I'll look farther afield.

Thanks for the interest and the tips.

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nandina

Something I forgot to address before. I think the research has pretty well confirmed that there ARE various ways to attract and kill cucumber beetles that are organic or semi-organic and safe. Micro-Flo had developed Slam for use on corn worms and Adios for the beetles themselves, using tayuya and Sevin. Adios was pulled off the market several years ago citing "lack of market interest". And I haven't seen any place where Slam can be purchased now. Then I read that Micro-Flo was in the middle of a lawsuit for illegally importing some unsafe insecticides, etc., and they're keeping a low profile. So with USDA approval delays and the primary company to develop this semi-organic insecticide being under serious fire, the entire commercial move toward safe insecticides to use against cuke beetles seems to have utterly languished.

Maybe it will eventually pick up again. In the meantime....

First, if your home garden trials work, you will want to publish this somewhere to share this knowledge.

Second, try a 'Blue Hubbard' squash as a trap crop, should be easily available.

Last, can't you spray some sort of a hort oil first then come along immediately behind and dust plants?

Dan

Hi, Dan.

Blue Hubbards have been tried as lures, and as such they are quite effective. The only problem is that they are quite vulnerable to the bacterial wilt spread by cuke beetles (the BIG reason you don't want the beetles in your garden at all), more so than most other squashes and gourds, and you don't want a sick trap crop that can spread the wilt to your other cucurbits. They aren't recommended as a trap crop for cuke beetles for this reason, though they grow fine in areas that don't have to deal with these pests.

I don't know if spraying horticultural oil first would work or not, but I'll certainly try it if other non-oily bases don't work. 'Twould make life simpler if the lure, dye, and base could first be mixed together and then the spraying would be a one-step deal. I don't see why the combination couldn't be sprayed on the leaves unless the oil is either repellent or obscures the scent of the lure or interferes with the action of the dye, lots of "if"s. Of course, you can't always have simple!

Gotcha anney.

Would some sort of clay - perhaps similar to what they do in organic pear orchards - be a viable medium for delivery? I'm having trouble picturing how you could get some sort of suspension in a one-shot spray that wouldn't' clog...

Dan

The point you are trying to prove is perfectly stated in your original message as follows, Let me emphasize, I'm looking for a natural non-toxic adhesive, not something that kills insects or protects from disease, etc.

You are not trying to kill the insects or protect the plant from disease, you are trying to prove the point that you can mix your lure into something sticky.

Molasses might be what you are after, but I'm not going to be surprised if you dismiss that. You've dismissed every suggestion so far. If you use molasses you might not prove your point because molasses also feeds the microbes living on the plant surfaces and those help to protect the plant from both disease and from insects. Part of the problem with doing plant research is that when you try to hold things under control, you end up over controlling something else.

dan_staley

Yes, clay is a possibility. Isn't that the carrier for Surround? It would wash off in the rain and certainly absorb the dye and perhaps even the lure to hold it on leaves.

I don't know much about liquid garden sprayers since I've only used a couple for foliar feeding. The spray holes would need to be large enough to accommodate at least small particles of the lure if a fresh slurry were used along with clay or any other base. So the application method is another consideration.

A wide range of possibilities has been offered, and I really appreciate them. Thanks to all who made them! Now on to testing!