Friday, August 29, 2008

The Monarchs have returned!

Have you seen them? They're baaa-aack! It always warms my heart a bit when I go outside to look at my milkweed and find monarch caterpillars or their chrysalis dangling on the branches.

Monarch caterpillars are pretty distinct. Obviously, they are a caterpillar, so they have a worm-like body that is yellow, white and black striped. The caterpillars have two long, black projections that look similar to antennae towards the head region and then two black shorter projections near the end of the abdomen.
The pupa, or chrysalis, is usually formed on the milkweed plant and starts off bright green with metallic gold at the top. The chrysalis will change colors as time goes on and the caterpillar transforms into a butterfly. It eventually becomes transparent and you can kind-of see the butterfly inside.

After the adult (the butterfly) emerges from the chrysalis, it spreads it's wings and stays in place for several hours to allow it's exoskeleton to dry and harden before it can fly away.

Friday, August 22, 2008

The Adventures of Rosie the Tarantula

I came back to the office last week with goodies for my wee-beasties. It was feeding time which usually happens every couple of weeks. I dumped a few crickets in with Debbie, my Goliath Bird-eating tarantula. She usually gets live mice about once a month, but she's been acting a bit odd lately and didn't eat her last mouse, so I think she's getting ready to molt. At this point I'm just waiting for her to get on with it. Next came Tiny, my Texas brown tarantula and the Scolopendra centipede. The centipede, as always, jumped on the crickets immediately. I came to Rosie's tank and imagine my horror and surprise when I noticed the lid was askew. For some reason, I still felt the need to search the tank for her, hoping that she might be in there somehow. To understand how ridiculous it was for me to do this, you need to know that the tank has substrate on the bottom and a water dish with gravel in it. I took all the plant material for hiding out last time I cleaned the tank because it was growing something. Even in my panic, I had to least it wasn't Debbie. People in the office would freak out if she got out since she's so huge!

So, what do I do now? Do I let someone know just in case Rosie wanders off? There's a pretty good space under my door that it would be no problem for her to get out of my office. Parts of the office are being renovated at the moment, so there is furniture, boxes, books, etc. piled everywhere in offices and hallways. My office has a pathway that allows me to get to my desk. There was no way I could go search for Rosie; there was too much stuff in the way. I decided that I was going to keep the matter of Rosie's escape to myself. Hopefully if someone found her they would come a get me instead of squishing her or maybe she'll show up crawling across the floor or up the wall one day.

Tuesday, I turned around in my chair to take one of my all too frequent trips to the restroom (BB likes squishing Mommy's bladder) and guess who was waltzing out from behind my mini fridge- Rosie! I quickly picked her up and put her back into her tank. This time I secured the lid with a large rock on one side and a marble award thing I had on my bookshelf. She's now happily chilling in her tank, resting up from her big adventure in the open.

Friday, August 8, 2008

It's not fall yet, so why do I have fall webworms?

While I haven't been getting many questions on them, I thought I would address fall webworms since I've been seen tons of webbing in trees all over town. Webworms can attack over 88 species of plants, but are often seen on pecan trees in Texas. We have 2-4 generations each year that start in the spring and continue into the fall. Fall populations are often the most damaging, giving the name fall webworms.

Caterpillars, the immature state, are very pretty in my opinion. They are about an inch long when fully mature and are pale greenish-yellow with long tufts of hair projecting from their body. Adult moths are somewhat drab with whitish coloring and small, dark spots on the front wings.

When caterpillars emerge from the egg, they immediately begin to spin the webbing that is expanded to cover the tree's foliage. The caterpillars use the webbing to protect them from predators. They enclose the foliage that they feed on and will expand the web size when they run out of foliage to eat.

So, options for managing webworms really depends on how annoyed you may be with the webbing, how large the tree is and what kind of effort you want to give to manage the caterpillars. Egg masses can be pruned or picked off the tree (egg masses are on the underside of leaves and typically covered with hairs). Pruning webs out of the tree or opening the webbing with a stick or stream of water can also help to manage populations. Pruned webbing should be disposed of in a sealed, plastic bag or dunked in a bucket of soapy water to kill the insects. Opening the webbing can allow predators to enter the web and help manage the pests. You do not want to burn the webbing out of the tree as this can often cause damage to the tree as well as being dangerous.

Of course, there are also chemical options. Less-toxic options include using active ingredients such as Bacillus thuringiensis variety kurstaki, also known as Bt. This variety of Bt specifically targets caterpillars, but will not differentiate between "good" and "bad" caterpillars, so avoid drift. Spinosad which comes from a soil microorganism is another option. Both of these chemicals must be consumed for them to work properly, so good coverage of the foliage is key (hence, you must open the webbing to get the chemical to where the caterpillars are feeding!). These options work best on smaller caterpillars (less than 1/3 inch).

For management of larger caterpillars, contact kill chemicals work best. Some active ingredients to look for include permethrin, cyfluthrin, carbaryl or acephate. Again, the chemicals have to get into the webbing where the caterpillars are located or they will not work very well.
Of course, you can always choose to let the caterpillars do their thing. The trees and caterpillars have been here living together for many, many years and nature always seems to find a balance of things on it's own.
Also, don't expect webbing to disappear from the tree once the caterpillars are gone. You will either have to wait for a heavy rain or use a high pressure water stream to knock the web out.

Friday, August 1, 2008

Grasshopper & Katydid Nymphs

Grasshoppers and katydids can be a common but unwelcome sight in the backyard garden. These insects can be pests in the immature and adults stages, feeding on a variety of plants causing holes in leaves or consuming large parts of the plant foliage. Unfortunately, people often wait until it's late in the season to attempt to manage these pests and end up trying to manage the adults. This doesn't always result in the best management. Adults can not only walk or jump to get away from treated areas, but they have fully developed wings and can FLY. Immatures, or nymphs, do not have fully developed wings and cannot fly, so they are a better stage to target management strategies.
For grasshopper or katydid management, you can try natural products with active ingredients such as spinosad, neem, d-limonene, pyrethrum or rotenone. There are also many synthetic products with active ingredients such as cyfluthrin, permethirn, bifenthrin or carbaryl. Of course there are also non-chemical methods to try such as vacuuming up the critters or using row cover to protect your plants. Remember, manage these pests early when they cannot fly away!