Issue: July 29, 2000

• Aphids on tomatoes
• Pot bound philodendron

Aphids on tomatoes

Can you please help me get rid of the bugs on my tomatoes? I think they are aphids, but I'm not sure. I've tried using liquid Sevin(R) but it doesn't seem to help. They have already killed one plant and are on several more. Your help is desperately needed. Julie

If the insects infesting your tomatoes are indeed aphids, very often the only necessary treatment will be to wash the insects from the plant with a strong jet of water. If the water is too forceful in a stream, it may do damage to plants, fruit, or flowers. A strong, fine mist or a strong, but not too intense, stream of water should suffice to knock many of the aphids from the plant. It will be necessary to repeat this treatment every few days. While the aphids are on the ground and while they are climbing back into position, they are doing no harm. However, even when they are not harming the plants, they are attracting predators which eat aphids. There are many such predators, so this can be an effective means of control.

If it is necessary to use insecticides, there are many labeled for control of aphids. It would be wise to take a sample of the insects to your local Cooperative Extension Service Office or to a good nursery to have the insects positively identified. Be certain you choose an insecticide product labeled for this pest and labeled for use on vegetable crops. There is also a ãharvest intervalä listed on the label. That is the number of days you must wait following treatment to harvest the vegetables. Read and follow all the label directions.

The Sevin(R) you mentioned may have killed some of the aphids, but they reproduce so rapidly that it may seem to have failed. This will be true of other insecticides as well, so repeat applications may be needed. Harvest all ripe and nearly ripe fruit before each treatment, then wait the required harvest interval before harvesting again and treating again.

Since the insecticide will probably kill the beneficial insects that eat aphids, once you begin treating it will be necessary to continue treating. The pest insects tend to return following treatments much faster than the beneficial insects.

It is possible to mix treatments. If the infestation is extremely heavy as you seem to describe, use of insecticides first, then treatment by washing away insects in subsequent recurrences may be sufficient to control the problem. Remember to get a positive identification before beginning treatments as this will make it possible for you to achieve maximum success.

Pot bound philodendron

I haven't had any luck finding the answer to my question in any of my garden/plant books and figured you could help me. I just bought a lovely philodendron— the type with the large, deep-toothed leaves that stand upright (not a climber)— and it seems like the pot is a little too small for the size of the plant. It is over two-feet tall. However, is this one of those plants that like to be root-bound? Tammy Artesia, NM

The philodendron you described, and many others, are quite capable of growing in amazingly small containers. Actually, this is true of many plants as long as their needs in the way of water and nutrients are met. In a small pot, you must water more frequently and fertilize regularly. I have seen philodendrons grown so long in small containers that the root mass inside the pot became large enough and exerted enough force on the pot to break the pot.

Just because the plant will grow in a very small pot doesn't mean that you must grow it in such a small pot. Moving it to a larger pot will probably allow it to grow more rapidly. Please remember to water less often in a larger pot because the ratio of roots to soil (and water) is much less in the larger pot (until the roots again overfill the pot).

Those plants that do best when pot-bound are often flowering plants. Some of these will spend more time growing in oversized pots, but in undersized pots their growth is limited and their flowering is enhanced. The philodendron is grown for its foliage, not its flowers, so pot size is not a primary consideration in the case of philodendrons.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

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