Urban IPM

Friday, June 26, 2015

Squash Vine Borer

My neighbor asked me why her squash seemingly died overnight. Unfortunately, I had to tell her about squash vine borers (SVB). If you grow squash in Central Texas, you are most likely familiar with this insect and it's damage. If you have not yet had the pleasure of encountering SVB, either lucky you or welcome to Texas or welcome to vegetable gardening!

Squash vine borer refers to a moth that lays reddish-brown eggs singly on the base of squash plants. When the eggs hatch, the larvae bore into the squash stem where they feed on the plant from the inside. So if the insect is on the inside of the plant, how can you tell if that's the problem? Typically, there is a hole in the stem where the larvae entered which has yellow sawdust-like frass coming out of it. Larvae overwinter in the soil, pupate, then emerge as adults in the spring to mate and lay eggs. Adult moths are about half an inch long with bright, contrasting colors. The abdomen is bright orange with black dots. The front wings are a greenish-black color and the hind wings are clear, but you typically don't see the hind wings as the wings are folded over the back when at rest.  Damage is death of the squash vine.  Usually it starts at the base of the plant and moves towards the outer parts.

If you have had squash vine borers infest your squash, vines should be removed and destroyed (not composted unless you are sure your compost pile temperature reaches high enough to kill insects) soon after squash harvest. Soil can be tilled before planting to reduce the number of larvae that are in the soil. Row cover can be used to protect new crops of squash you may plant, just remember to remove the row cover when the squash has blooms to allow pollination to occur (or hand pollinate). If you leave the squash uncovered, monitor the stems regularly for eggs and squish the eggs before larvae emerge.
 
You can also try to remove the borer from the stem before too much damage occurs if you catch the infestation early enough. Slit the stem lengthwise with a sharp knife, remove the borer and then cover the cut stem with moist soil and hope it takes root.  Some people may have better luck with squash varieties that root wherever they touch the ground.
On another note, have you been tuning in for the All Bugs Good And Bad FREE webinar series? If you missed one (or all for that matter), you can still listen and get great information!
Here's a link to all of the webinars for 2015.
http://www.extension.org/pages/72197/2015-all-bugs-good-and-bad-webinar-series#.VY2DlFJCjV9
For the webinars that have already occurred, you can click on the topic you are interested in learning more about and it will load that presentation page. At the top right corner there is a "watch recording" button. Click on that and you will be able to listen to the webinar.

Thursday, June 11, 2015

Chiggers

Ahhhh....the joys of rain.  While we haven't had rain in the past week, we are still dealing with the rain the we got in May.  I've been getting a lot of questions about mosquitoes of course.  I've also been getting questions on chiggers.  This is one that we really haven't had to deal with since it's been on the dry side.

Chiggers are the larvae, or immature stage, of a mite. These larval mites climb onto people when they walk through infested areas. The chiggers climb up the person's body seeking out a suitable feeding spot. They prefer to feed in areas where skin is thinnest or where clothing fits tightly. This often leads them to ankles, waist area, behind the knees, armpits and the groin area.

Chiggers do not- let me say that again....DO NOT- burrow into the skin as many people believe. "Smothering" them by painting the bite area with nail polish will not do anything to relieve discomfort. Instead of burrowing, chiggers inject a digestive enzyme into the skin which breaks down skin cells. The chiggers eat the broken down skin cells. Itching and redness from chiggers is caused by the body's reaction to the enzymes chiggers inject. Itching typically begins 3-6 hours after being bitten, peaks at 24 hours and may last up to 2 weeks.

Try to avoid chigger infested areas. If that is not possible, then here are some suggestions:

  • wear protective clothing: tightly woven items that fit loosely that include long sleeves and pants with shoes and boots
  • tuck pant legs into boots
  • avoid sitting on the ground
  • remove and launder clothing ASAP after being in infested areas
  • shower/ bathe after being in infested areas; scrub vigorously with a washcloth
  • before entering chigger infested areas, use an insect repellent with DEET or picaridin
To treat chigger infestations around the home, try the following:
  • keeping the lawn mowed
  • maintain vegetation; do not allow vegetation to grow high and keep brush cleared
  • fill in any low lying areas that remain damp or moist
  • try treating with residual pesticide sprays (pyrethroids)- read and follow all label instructions!

Friday, May 29, 2015

Flooding and fire ants

I think saying that weather has been interesting for Central Texas as of late is a bit of an understatement.  We have had so much rain that has led to flooding in multiple areas, causing much loss and devastation. While clean-up efforts are underway for various parts of the state, people need to be aware of fire ant movement.  I know this is one the the last things on everyone's mind when looking at the results of the flooding, but it can be important information for those people who are allergic to fire ants.

We all know that red imported fire ants live in the soil.  What happens to them when we have flooding?  Many people may think that they will drown in the flood water.  Unfortunately this isn't true. 

When fire ant colonies are flooded, the ants form living raft by clinging together.  They float along the water surface until they hit dry ground, a tree, rock or other dry object.  Once they come into contact with a dry area, they emerge from the flood waters and take shelter anywhere possible until they can re-create a colony in the soil.  Living rafts of fire ants can take on different shapes from long ribbons to mats to a ball of ants.

Any floating mats of fire ants that are encountered should not be touched or disturbed.  Do not touch them with sticks or other objects as the fire ants will quickly grab onto the object. If working in flooded areas, make sure to wear appropriate clothing.  Long sleeves, pants and gloves will create more of a barrier against fire ants reaching skin where they will bite and sting.  Be aware that fire ants could be hiding anywhere that was flooded.  Wear gloves when picking up debris or other objects.  You may want to spray insect repellent containing DEET on your shoes and pants.

If you encounter fire ants in debris, use a fast-acting contact pesticide labeled for ants, but make sure the products are not sprayed into water as they can be toxic to aquatic organisms.  Fire ant baits should not be used after flooding because many of them are slow acting and colonies will be disorganized and not foraging for food.

Also be aware that fire ants may be showing up in areas that may have not had them previously or areas that were treated.