Tag Archives: pest

The Good, the Bad and the Ugly

July 22, 2017

The Good, the Bad, and the Ugly

Dog days of summer are here. Tomatoes are ripening, zucchinis are looking like footballs and aphids are blanketing the vegetables and flowers. With no rain to help wash the pests off, what’s a gardener to do?

In order to grow plants organically, the first step is to identify the pest that is eating your plant and understand its life cycle.three-bugs-smwp_20170701_004

See chard leaf photo attached. The good – the yellow ladybug eggs. The bad – the white leafminor eggs. The ugly – the black aphids and aphid eggs.

There are many beneficial insects, such as ladybugs and parasitic wasps, that feed on pests. Ladybug eggs will hatch and can eliminate a patch of aphids in no time. It is important to learn what both the eggs and the larvae of these friendly predators look like so that you don’t accidentally kill them.

Aphids are one of the most common pests we find. They come in many colors and attack a huge variety of plants. Aphids are small, soft bodied insects that suck the juices out of stems, leaves and buds. They can reproduce without mating and give birth to live aphids that do not have to pupate. As long as the temperatures are warm enough, they will keep breeding and feeding. They secrete a sticky residue called honeydew that ants love so much that they will protect aphids from predators.

Sat, Aug 5, 10-12, Work Party
Sun, Aug 20, 2-4, Work Party
Sat, Sep 2, 10-12, Work Party
Sun, Sep 17, 2-4, Work Party
Plus Thursdays 10-12, Food Bank

Another common pest on Swiss chard, beets, spinach and sorrel are the beet and spinach leafminers. Leafminer flies land on the undersides of their preferred plants and deposit tiny pale eggs. The eggs hatch and the larvae mine into the leaf tissue, creating “tunnels.” When the tunnels run into each other, the leaf tissue turns brown and dies. The larvae drop to the ground, pupate and begin another generation of flying adults looking for a place to lay eggs.

Aphids and leafminers can do a lot of damage, but they usually don’t kill plants. Leafminers overwinter in the soil, so I recommend you rotate crops and avoid growing chard and beets in the same bed every year.

sue-and-food-bank-bed-wp_20160509_001You can tent your plants with fabric (floating row cover) that lets through light, air and rain to help prevent flying insects from landing on plants. Check weekly for eggs and larvae as a few will manage to get into the tent. If eggs hatch and you catch the larvae early, you can lessen the damage by smashing them or dislodge them with a strong spray of the hose. Or, use a soft brush to knock off aphids, larvae or eggs. Harvest damaged leaves, cut away the damaged parts, and eat the rest. More food for you and less for the pest!

UC Davis Integrated Pest Management has great photos and information about many insects, good and bad.

Aphids: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7404.html
Leafminers: http://ipm.ucanr.edu/PMG/GARDEN/VEGES/PESTS/vegleafminers.html
Ladybugs: http://ipm.ucanr.edu/PMG/NE/convergent_lady_beetle.html
Parasitic wasps: http://ipm.ucanr.edu/PMG/NE/lysiphlebus_testaceipes.html

Sue Hartman

Winter Moth on Attack

May 3, 2017

On April 21, I noticed a rolled leaf on the Twinberry at our house. I shuffled over to our apple tree. best-of-back-wp_20170427_001Hmm. More rolled leaves. I jogged up to the orchard and every fruit tree that had leafed out showed this same leaf damage. What was this small green larvae with a stripe down it’s back?

The Honeycrisp got hit hard since the pest arrived just as the tree was leafing out. The fruit gods had mercy on the William’s Pride and Liberty because they were ahead of the curve at full blossom stage.

best-of-tail-wp_20170427_008The larvae had certain characteristics: an udder like organ toward the back end and also a two-barrel exhaust at the tail.

You can’t have a good management strategy without knowing which critter you have. So, I looked at pages and pages of moth larvae on the internet. The closest I could come was the light brown apple moth. Lucky for us in Washington, it was not that. The larvae of the light brown apple moth have an anal fan of forklets.

Chris Looney, from WSDA came to the rescue to identify the pest as the winter moth (Operophtera brumata). (It’s within the group called loopers or inch worms.) It is common in our area and is not a leafroller, even though it rolls leaves. Its behavior is described more as sticking one leaf to another with its silk but, in fact, I can tell you it also rolls the leaves to make a nice hiding spot.

The udder looking appendage is actually called abdominal prolegs (versus the true legs up front) and the dual exhaust is simply the anal proleg.

“Damage to blueberry and apple crops is especially severe as the reproductive parts responsible for fruit can be destroyed before buds open fully.” (https://ag.umass.edu/landscape/fact-sheets/winter-moth-identification-management)

You can say that again. Just as the flower buds peek out and huddle together between tight cluster and pink stage, the caterpillar attacks.

Tree trunks can be checked for the tiny orange eggs during the winter. Eggs hatch when temperatures average around 55 degrees. Winter moth larvae are active for only about three or four weeks. After they have had their fill, they will dangle down to the ground on silk and burrow into the top layer of soil, where they will become dormant pupae until emerging as adult moths in late fall for their nighttime mating. The flightless females will climb up trees lay eggs on the tree bark, and die. Then next April those eggs will hatch and the cycle begins again. (http://www.arborcaretree.com/winter-moth-article.htm)

Sun, May 21, 2-4, Work Party
Sat, Jun 3, 2-4, Work Party
Sun, Jun 18, 2-4, Work Party

For organic management, we will try a dormant oil spray to focus on destroying the eggs this coming winter. This might only be partially satisfying since eggs are deposited virtually everywhere on trees and shrubs and new caterpillars can quickly migrate from untreated areas to the oil-treated plants by ballooning via their silken threads.

When applying oil sprays, temperatures should be above 45°F. Avoid spraying when temperatures may dip below freezing for 24-48 hours after application. (Temperatures below this threshold increase the risk of causing injury to the plant phytotoxicity – https://tinyurl.com/laqhckl). Certain weather conditions, such as when it is cool and cloudy, can also delay drying time and enhance the potential for injury. (https://ag.umass.edu/landscape/fact-sheets/winter-moth-identification-management)

Look-alikes: Blueberry sawfly (does not have pale stripes along body) Cankerworms (has two pair of prolegs, one shorted than the other), Bruce spanworm (found in the Northeast U.S.)

If anyone is interested, we are paying a bounty – 10 cents per larvae! Tell your friends about this lucrative offer.

Ruth