Bugs of Summer
In the summer, bugs become pests when they start to attack our plants. Unfortunately for our friendly bugs, it's common practice to indiscriminately kill all bugs, even when they're actually beneficial. Sorry pollinators, fireflies, and lady bugs! So when a bug does cause a problem, using the lowest impact way to try to manage it makes sense for our friendly bugs, the ecological health of our landscapes, and our water quality.
Prevention
- Plant a diversity of species marking it harder for any one pest to thrive.
- Get to know your plants. Some plant and insect relationships are notorious, such as spider mites on lantanas and black spot on roses. Knowing when and where a problem is most likely to occur gives you an advantage over the pest.
- Keep plants healthy; it is the best way to ward off attackers.
Monitor
Be on the lookout. Catching an infestation in an early stage makes it easier to control the problem. This is as simple as taking a stroll through your garden at least once or twice a week. Look carefully for discolored or deformed growth, and chew marks. Always look under the leaves and on the ground near the base of the plants for signs of damage.
Diagnosis
- To make informed decisions about potential action, be sure to find the real culprit. Is the problem an environmental or cultural one? Perhaps too much sun/shade, over/under watering? Or is it an actual pest?
- Knowing the type of damage a particular insect causes greatly helps in its identification. Diagnosing plant damage from bugs can be differentiated into two main categories based on their mouthparts. They either have piercing/sucking or chewing mouthparts.
- For assistance diagnosing plant problems see the Diagnosing Plant Problems fact sheet or call the Travis County AgriLife Extension Service at (512) 854-9600.
Two Common Bugs of Summer
Insects with piercing and sucking mouthparts do just that, they pierce leaves and suck plant juice leaving little yellow speckles or whitish pin pricks on leaf surfaces. Severe infestations can completely discolor, distort and mottle the foliage.
SPIDER MITES
Left - Spider mite damage on leaf
Right - Spider mite webbing from severe infestation
Spider Mites cause tiny specks on leaves and make webs around and under leaves. They prefer hot and dry conditions. During the initial infestation, the mites and their webbing can be hard to see. Take a piece of white paper and shake the potentially infected foliage over it and look for the tiny mites crawling over the paper.
APHIDS
Left - Lady bugs eat aphids that are attacking new growth
Right - Lady bug larvae (the alligator-looking bug) eating aphids
Aphids are found on new growth because it is easier for their piercing-sucking mouthparts to penetrate the plant tissue. They are soft-bodied little insects that come in many colors. If they are starting to deform new growth it is probably wise to take some action.
Low Impact Treatment
- Try to eradicate the spider mites and aphids by spraying them with a stream of water to dislodge them. You will have to be persistent and do this at a minimum once a week. Be sure to spray under the leaves.
- If that doesn’t work, try using an insecticidal soap. These products have little if any toxicity; it doesn’t poison the insect but it physically damages it. The soap spray needs to come in contact with the insect. After the soap dries the remaining residue is not harmful to any insect that comes in contact with it.
Getting rid of every single pest is not necessary or practical. Before using any pesticide correctly identify the problem and its severity. If using a pesticide, choose a low impact product. Always read the label and follow the directions.
For more earth-wise gardening information go to www.growgreen.org or pick up fact sheets at Grow Green distribution sites in the Austin area.
Article submitted by Denise Delaney, Environmental Program Coordinator, Watershed Protection, City of Austin.