Dear Umbra,
I have a pest problem in my backyard -- specifically, some tiny (but apparently hungry) insect is making lace out of my basil leaves. I do not want to use pesticides for many reasons, not the least of which is that I cook with the herbs I grow.
I think I have found a "natural" solution, but I wanted to consult you first. My garden-supply store sells praying-mantis egg cases ("The natural pest control solution! Over 200 insects inside! Hang on a tree and eggs will hatch when temperatures stay above 70 degrees for three weeks!") The store also sells bags of dormant ladybugs for the same purpose. My question is: should I buy these bugs? Or will unleashing them just upset the natural balance and biodiversity of my rather small backyard?
Bugged,
Lindsay Ratcliffe
Helotes, Texas
Dearest Lindsay,
It's common to see these entrapped insects in garden stores now, and sustainable farmers often use beneficial insects for pest control, but they are not a cure-all. Before you do anything to deal with your basil perforator, you need to take the official First Step of natural pest control: positively identify the pest. Without knowing what is causing the holes, you can't take an effective step to stop it/them. Let's identify together, and then I'll get to your main question.
Pray tell, which way to the buffet?
Photo: iStockphoto
Usually I would use a pest and disease book I got at a used bookstore, from the Rodale Organic Gardening imprint, but today the internet will connect us all. Before looking it up in any book or computer, one should go out and look closely at the plant. One may actually see the pest in action. If not, note where the damage is happening -- on all leaves, on the oldest leaves, on the stem, etc. -- and hazard a guess as to whether it looks like an insect or a disease. Next, on to the internet. I'm entering "basil pests" first and getting several websites describing major pests of basil, which include aphids, slugs, Japanese beetles, white flies, grasshoppers, and flea beetles. Further limiting the search with "Texas" gets me to Texas Extension, and they only suggest Japanese beetles, then I'm on to "Japanese beetle damage" -- whoa. Ick. That's pretty dang lacy. You get the idea. After you have identified which pest is damaging your plant, find out what its predators are. If neither ladybugs nor praying mantises consider your pest to be dinner, part of your question is answered ("no").
As an aside: step two of natural pest control is to do a series of less-toxic interventions. These include habitat modification (killing the host plant, removing the places where pests nap, etc.), mechanical control (this includes squishing and picking off), barrier techniques (deer fence is an example), and less-toxic pest controls (this is where the ladybugs come in). Last resort would be the toxic interventions.
Back to your question.
If ladybug or mantis dinner is in your garden, we have the larger question of whether buying insects and releasing them is worth the money, and your concern about destroying your yard. I don't think it's worth it. Mantises are general predators. Although they might eat your mystery pest, they might also eat the various unsung beneficial insects already in your yard (aka, destroy the yard, although destroy is too strong a word), and they might eat each other, completely defeating your primary purpose. Ladybugs eat aphids and a few other soft-bodied insects. The Asian multicolored ladybug is an introduced species that is displacing native ladybeetles -- you may have Asian lady beetles infesting your home. Here are some tips to avoid such a fate, and photos to help identify your own ladybugs. If you release ladybeetles, a few might land, eat, and breed, but it's likely that the bulk of them will fly away, and this is why I think ladybug sales are hokum. If you have aphids, any ladybeetles already in the vicinity will eventually come find them and eat them. I don't know how they find them, maybe smell.
A big part of pest control is creating a yard (and neighborhood) in which natural predators and beneficial insects such as spiders, beetles, and ladybeetles live and reproduce, adding to the yard's diversity. This won't mean you have no pests, alas, and when you find out what is eating your basil you'll still have to find out how to stop it. For your sake, I hope it isn't Japanese beetles.
Preyingly,
Umbra
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Comments
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BMendenhall Posted 2:49 am
16 May 2007
Birds are great natural pest controls that eat insects so creating a bird-friendly habitat can also help. Use of toxic pesticides is a real turn-off for birds. Better than using pesticides to eradicate the problem is, as Umbra suggests, removal of the distressed plant - at least for this year. Work on building your soil and your environemnt and try basil again next year. Or try planting it in pots in another part of the yard. Or trading what you have growing well with someone else who has a good crop of basil.
I would also go for the praying mantises and ladybugs - they do help, they are fun to watch, and they change the habitat for the better since they do start to get established if you've created good conditions for them. They are also a strong incentive not to be tempted to use toxics cause once you have a resident population of mantises or ladybugs you won't want to spray.
Barbara
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kyotousa Posted 4:05 am
16 May 2007
Our garden is full of life, and yes, it includes slugs, aphids, and earwigs and other critters that vendors of toxic chemicals love to portray as pests to extract millions of dollars from us that could be better spent on compost bins, bat boxes or backyard beehives. You do not need to expose yourself, your family, your neighbors, and the other equally important life forms that inhabit the planet to long-lived poisons that are unneccessary for a healthy garden.
Bugs of all sorts play an important role in achieving the type of balance that allows everything else to flourish. Do they occasionally nibble a tender shoot? Sure, but they also provide a food source for the other birds and insects that you want spending some time in your yard. Overtime, and as the balance of your yard improves (improved soil, variation in type, size, and density of plants, sources of water, places for insects to reside) you'll see a greater range of creatures taking up residence. And you'll see your garden with new eyes and find yourself thrilled that the basil has been munched, knowing that your actions have made a contribution to the health and well-being of your garden, your neighborhood, and the planet.
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atlasgrrl Posted 4:46 am
16 May 2007
I'm in Texas too (Austin), and I LOVE J Howard Garrett's "Texas Organic Vegetable Gardening." In addition to really helpful info about growing specific fruits and veggies, there is a chapter about organic pest control.
The book includes info on beneficial insects - ladybugs, ground beetles, fireflies, lacewings, nematodes, predatory mites, praying mantises, spiders, and wasps... some of these amy already be in your backyard! You can introduce others, but most will leave. Those that stay will work on keeping pests in check, but they'll never really be able to eliminate them.
SO - If you have a pest infestation (which it sounds like your basil plant has), you may want to use some kind of organic pesticide on the specific plant. Depending on the pest, there are several non-or-less-toxic solutions that you can apply to the plant. Molasses, citrus oil, diatomaceous earth, garlic-pepper tea, Bt, compost tea... which one you use totally depends on the pest, so as Umbra said, it's important to identify it correctly.
If you have trouble identifying your basil chomper online, you can put a few leaves and bugs in a sealed plastic sandwich bag, and take it to your county Cooperative Extension agent(s). He/she/they should have no problem identifying it, though they may counsel heavier-duty pesticide solutions. Just nod your thanks, and then go home and use something a little safer for you, your soil, your plants, and all of the little critters - good and bad - that enjoy your backyard too.
P.S. Bexar County's Extension Office can be found online here: http://bexar-tx.tamu.edu/
P.P.S. I have no connection with J Howard Garrett, I just really like his book. Promise.
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Wild Flora Posted 5:24 am
16 May 2007
Insect outbreaks follow a typical pattern: The population of pest insects skyrockets, which eventually attracts predators. Once the predators are assured of a reliable food supply, they breed, which produces a lot more predators. The pest outbreak then begins to subside as pest insects are gobbled up. But this process takes time. If it's disrupted (for instance, by an impatient gardener who decides to resort to pesticides), it may never happen at all.
Sometimes predators can't keep up with an insect outbreak, of course, which is why Umbra is quite right to say that it's best to know what you're dealing with. However, it's amazing how often patience pays off. Your friendly local predators will come to the rescue--but you have to give them a chance!
Incidentally, Umbra is also quite right to warn people off importing insects to the garden. If you provide good habitat and avoid using pesticides, most likely there are plenty of local predators, from lady beetles to wrens and other birds, that will be more than happy to control pest insects for you.
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sernya Posted 6:19 am
16 May 2007
The Praying Mantis is an invasive species in our region, and is killing many of the bugs that are neccessary to a healthy praire. Make sure to do research, and keep them out of your region if they shouldn't be there! Invasives can do a lot of damage, especially if you are trying to restore landscapes!
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jessifromdenver Posted 8:37 am
16 May 2007
Aphids, usually, will not kill the plants that they infest if they are large plants, like trees and rose bushes, although they are messy and unsightly. Also, they produce a sugary waste that attracts bees, wasps and other creatures that sting and frighten children, which was the biggest complaints about them we got. But, as irritating as they may be, they will most likely all die come winter and will only be a problem for one summer season.
Lady bugs and praying mantis do not work well for the main reason that there are too many of the aphids to eat. For most of the year, each generation of aphids are born already pregnant with the next generation of female aphids, and millions of pregnant aphids are born to the mommy aphid within a few days of her birth. It takes a ton of lady bugs and praying mantis to keep up with that. Most lady bugs do fly away, and although a praying manis egg will hatch up to 200 little, baby mantis (which are very cute, by the way, the sort of dance), most of them eat each other and you only end up with the one or two strongest, who will proceed to fight to the death or mate if they ever run into one another, and if they mate the female will eat the male when they are done! The best way to get rid of aphids, if you must, is to use mildly soapy water. Spray down a tree and wipe down the leaves and branches of a smaller bush.
If you are going to release lady bugs the best time to do it is in the evening. That way they will be more likely to land for the night and hopefully when they see how many bugs you have they will be less likely to leave in the morning, but still many of them proceed to fly off. They do not have logic like we do.
At least, this is what the horticulturist at our garden center taught me.
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liese Posted 12:36 pm
16 May 2007
Correction to the article: toxics are not a last resort. They are not a choice. If it's the wrong plant in the wrong place, change the place or the plant. Period. It's too important- they don't just go away.
-liese
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nattydad Posted 1:44 am
17 May 2007
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Lindsay Posted 8:22 am
17 May 2007
And I'm definitely going to look for the Rodale and Garrett books.
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Pandu Posted 11:40 pm
17 May 2007
Ordering bugs in the winter should be done during a warm spell. That's been getting easier in recent years. I've had excellent service ordering from http://www.planetnatural.com many times. This past winter we ordered directly from a ladybug breeder, but a two-week shipping delay resulted in 99% dead ladybugs on arrival, so we went back to Planet Natural when it warmed up again. We had a dense population of perhaps thousands of aphids on our Angel's Trumpet plants, and the ladybugs eraditcated them in about one day.
....
Incidentally, the new internet filter at my state job blocks Gristmill. Apparently it's even banned during lunch and breaks. Oh well.
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girlonfoot Posted 4:06 am
21 May 2007
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hankerson Posted 1:01 pm
25 May 2007
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