How to tell what ails your plant

SANDY R. OF SANTA ROSA ASKS: How can you tell whether a plant has a pest or disease issue, or if the symptoms they’re showing is caused by something else, like overfertilizing, overwatering, etc?

Plants can show signs of abnormalities in many ways as they’re growing. Sometimes these abnormalities are due to harmful pests or diseases. Other times the symptoms are from another underlying cause, such as cultural, environmental and mechanical, which can often be reversed if a diagnosis is made early and treatment begins quickly.

When a plant is suffering from cultural or environmental stresses, these disorders are called abiotic, meaning they are caused by physiological (nonliving) issues rather than biological (living, or biotic). Abiotic disorders include weather, soils, chemicals, mechanical injuries, cultural practices such as watering, or genetic traits. Abiotic plant problems can sometimes look very similar to biotic plant problems. By learning some of the more common environmental stresses, you, as a gardener, will be able to diagnose an abnormality on a plant. The more familiar you are with abiotic symptoms, the less likely you will be to reach for sprays and fertilizers that may do more harm than good in your garden.

With careful examination, you can possibly determine whether the problem is abiotic or biotic. One of the quickest and easiest ways is by examining the newest leaves of the plant. If the new leaves look healthy, and all the old leaves of the same age look bad, the problem is, or most likely, abiotic.

Here are some of the most common abiotic plant disorders: Air pollution, blossom end rot, fruit or root cracking, flowering/bolting, fertilizer/pesticide burn, herbicide damage, mechanical injury, moisture imbalance, nutrient imbalance, poor pollination and sunscald/sunburn.

JIM L. OF WINDSOR ASKS: I DO NOT want to buy a product for my flowers and vegetables that is a neonicotinoid insecticide as I have heard, and read, that these products are contributing to the death of our bees. Can you share with your readers what products we should stay away from?

Unless you know you are buying certified organic transplants from the nursery you may be introducing the persistent neonicotinoid insecticides into your garden, and therefore, into your food. As it has reported, neonicotinoids are potent, systemic pesticides that move through the plant and contaminate the pollen and nectar. The lingering poisons persist in soil, where they can be absorbed by crops. Neonicotinoids are one of the culprits known to be contributing to the bee’s colony collapse disorder. This a phenomenon that has been linked to the large number of deaths of the honeybees over the past several years. These pesticides are also suspected of injuring and killing many bird populations. The continued widespread use of neonicotinoids means fewer insects, which means less food for birds.

Neonicotinoids are widely used by farmers, and many garden centers and nurseries sell plants that have been treated with them. What this means is that the bees are probably being poisoned by the nursery plants you’re bringing home.

The Xerces Society for Invertebrate Conservation reports that the following brand names may

contain neonicotinoids: Please avoid buying these products and read the label.

Bayer Advanced 3-in-1 Insect, Disease, & Mite Control

Bayer Advanced 12 Month Tree & Shrub Insect Control

Bayer Advanced 12 Month Tree & Shrub Protect & Feed

Bayer Advanced Fruit, Citrus & Vegetable Insect Control

Bayer Advanced All-in-One Rose & Flower Care concentrate

Monterey Once a Year Insect Control II

Ortho Bug B Gon Year-Long Tree & Shrub Insect Control

Ortho MAX Tree & Shrub Insect

Bayer Advanced All-in-One Rose & Flower Care granules

Green Light Grub Control with Arena

Ortho Bug B Gon Garden Insect Killer

Ortho Bug B Gon for Lawns

Ortho Flower, Fruit and Vegetable Insect Killer

Ortho Tree & Shrub Insect Control Plus Miracle Gro Plant Food

Ortho Rose and Flower Insect Killer

Ortho Rose Pride Insect Killer

Dana Lozano and Gwen Kilchherr are garden consultants. Send your gardening questions to The Garden Doctors, at pdgardendoctor@gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.