What’s Bugging You?

Spots? Holes? Teeth marks? These are just a few of the indicators that you may have uninvited visitors to your garden. Some are ugly, some are annoying, some just plain obnoxious but some may be necessary. Yup, I said necessary! I’ll be talking about determining what you have, how bad it is and whether you need to do something about it.

Is the damage devastating your plant? With herbs & veggies it’s often a good idea to remove any critter, since these plants are often more susceptible to damage and the damage can get out of hand quickly.  If there are only few handful of leaves that are damaged (say 20% or less) I recommend you just let it go. I say this because often the insects are just passing through and by the time you note the damage, they are probably gone. If this is the case (as it often is with grasshoppers, for example) then spraying or using anything, organic or otherwise is useless. You’ll save time and money and not adding to the existing problem of chemicals in our water table.

Now to determine what it is you are looking for. Is it taking chunks out of the leaf or fruit? Is it leaving marks on your leaves? Is it creating a web or cocoon? Are there ants running up and down the branches?  What evidence the uninvited guest is leaving is a clue to where to look, whether it is a good guest or bad guest and how serious you may need to get.

Grasshopper damage

Chunks: This is an indication that what you are dealing with is a pest with jaws for eating plants. These could be from birds, grasshoppers, locusts, caterpillars, beetles, slugs and snails. Look carefully among the leaves and along the undersides of twigs, leaf stems and branches for these pests. Bird damage is often seen without the culprit being observed doing it and more often on fruit. Of course, different plants and different parts of the country have their own special set of guests, so it is good to look up what pests your plant might be susceptible to. Once you spot the little darlings, see if you can determine what kind of critter it is. A website called Bug Guide is a good starting place if you have trouble. It has a page where you can upload a photo of your "guest" if you don't find it on their website.

You can also spray the plant’s leaves with water and see if anything flies off. Usually grasshoppers will take off and this may be your answer. Grasshoppers, while they can take large bites out of the leaves don’t normally devastate a plant. They munch for a bit and then move on. Now, I don’t know if this is an old wives’ tale or not but I had heard they behave this way because if they stripped the plant, then the birds would be tipped off to their presence and swoop down and they would become dinner! However, this does not hold true for actual locusts, they don’t stop until they’re done. If they were your problem, you'd wake up to nothing but stems....if that!

Usually repeated applications of an organic insecticidal soap helps minimize any unwanted pests. This helps make the leaf unpalatable to them. Certain organic and synthetic mixtures will also have poison in them to kill off the pest. Just make sure you read the label in relation to using around edible plants as well as animals & kids. Remember also that many sprays and systemic treatments can often be non-selective. This means that any critter is fair game…. Good or bad!

Aphids - Can be a variety of colors

Discoloration or markings: Often a plant’s biggest problem is the sucking kind of pest, such as aphids, mites, scale, mealy bug, leaf hoppers, some beetles, leaf miners, just to name a few. Snails & slugs actually scrape the leaf surface to ingest it. These garden crashers will suck the sap out of the leaves, leaving them susceptible to other issues such as fungi, mold and other diseases. This behavior removes the sap from the plant leaf or stem and weakens it. This can cause it to die or creates a new problem such as disease.

Spots on the leaves or fruit can also be an indicator of disease, poor watering practice, chemical burn, fungus or nutritional deficiencies. There are so many possibilities that I can’t cover them all here. When watering, spraying chemicals or fertilizers; try to avoid getting any on the leaves or fruit and spray according to the label directions on strength and time frames. On foliar fertilizers or insecticidal soaps that need to be on the leaf to work, generally you spray early in the day before the sun hits the leaf directly. You want the liquid to dry so that the sun doesn’t turn it into a magnifying glass and burn the leaf. Also, if you spray too late in the day, the liquid may not dry sufficiently and you may create another problem – fungus or powdery mildew. This can happen when the evening/night temps are cool, or humidity is high.

There are ways to control these pests as well as some of the diseases, such as a systemic  or foliar spray for disease control, organic insecticidal soap or beneficial insects such as ladybugs, mantids or Lacewings. There are chemicals that can do this as well, but just remember that often you have to spray at specific intervals for it to be effective. Pay attention to the harvest times if you are using it on your edible plants! Some products can become ineffective if it rains, or if they are hit by the sprinklers. This is not as big an issue as it once was, but read your labels carefully. One of the brands that I think is working at becoming more responsible is Bayer. Yup, the aspirin one. They have a line of home & garden chemicals that are more environmentally responsible than most. If you don’t want to wait for the organics to work or cannot invest a lot of time in the organic route, check out Bayer. They are often carried by home improvement centers and your local nursery. They have one for fruit trees that is only necessary to use once a year (known as a systemic because it is poured at the base and taken up through the roots to the rest of the tree.) A systemic is not normally used on veggies or herbs since they are so short lived however the Bayer product can be used on specific ones and does give which plants it can be used on and harvest time frames. If you don’t find your particular plant, don’t use it until you’ve called their helpline, just to be safe.

Some pests actually work from the inside out. Like the leaf miner and some caterpillars. They tunnel into the leaf or stem and lay their eggs. The larvae hatch and proceed to eat their way through the area. This causes odd markings on the leaves or stems. In more difficult cases you may need to use a systemic, such as the Bayer Fruit Tree or even the Bayer Tree & Shrub systemic to help the plant fight it. Organics would need to be applied when the adult insect is expected to visit the plant to prevent them laying the egg that causes the damage.

Leaf miner damage

On a side note to all that live in So California and are experiencing the Citrus Leaf Miner problem: The Citrus Leaf Miner attacks new growth, so it’s difficult to eradicate. Even using a systemic (such as the Bayer Fruit tree one) can slow it down but rarely does it stop it completely. It is best to limit the pruning of the trees to avoid pushing new growth. If you must prune, it is best to do so in late fall to mid-winter. The pest is normally inactive then and any new growth you may get won’t be as susceptible. While it is unsightly, the damage normally isn’t that detrimental to a healthy tree and the time & money spent on prevention or eradication would not be worth it. Make sure you remove all dropped leaves and any clippings from pruning and place them either in a closed trash can or a bag you can close. This helps prevent any possible insects on these items to get back to the plant.

ANTS! I have had numerous people come to me upset because they see ants in their plants, running up and down the branches and leaves. They think the ants are killing their plants when in fact ants are actually an indicator that you have another issue. This could be mites, aphids, scale or mealy bugs, to name a few. The ants are actually harvesting the “honeydew” or excrement from these pests or feeding on the eggs or larvae. The ants become a problem when they protect the insects from predators that would normally take care of these insects. By eliminating the initial problem (the mites, etc) you will remove the ant problem. They won’t stay where they don’t have food.

A note on using beneficial insects: If you try to use them preventively you will probably fail. They will only remain if there is food for them to eat. (You wouldn’t go shopping at an empty grocery store, would you?) Wait until you actually see a problem before purchasing any beneficial insects, and then apply them as directed. Some beneficial insects, like ladybugs, need to be released in the evening so they don’t automatically fly away. You could also lure beneficial insects into your garden by planting a diverse palette of plants. If you only plant one or two species of plants all over your yard, you run the risk of losing them to an invasion of pests or being wiped out by disease particular to that plant. The healthier your plants are and the more variety you have, the chances are you will have fewer pest problems.

I know it seems a bit counterintuitive to allow pests to live in your garden, but aside from the damage they may be doing, you will also be feeding the beneficial insects which in turn feed larger animals (birds).  This brings diversity to your yard that is essential to healthy plants. It’s all part of the food chain!

Mary

A good reference book is Insect, Disease & Weed I.D. Guide by Jill Jesiolowski Cebenko & Deborah L. Martin as editors. It is published by Rodale Press

Some chemical controllers:

Bayer Fruit, Citrus & Vegetable Insect Control - Systemic

Bayer Tree & Shrub Insect Control - Systemic

Insecticidal soap

Beneficial insects- Check your local nursery for more info for your area

Ladybugs

Decollate snails – good for the brown snail & slugs. Decollates are carnivorous snails. Once done, they usually move on. If nothing is available for them to eat, they may resort to eating decomposing plant litter.

Mantid casings (Praying mantis cocoons, awesome for kids to observe! Each casing can hold upwards of 50+ mantid!)

Green Lacewings

Assassin Bugs

Stinkbug

Minute Pirate