Question
What give house plants bugs? I have a Peace Lily, with tiny   little bugs moving on top of dirt and fruit flys flying around in the house. The new blooms are turning brown on end before the leaf opens up, What cause's this? What do I need to do to treat my Peace Lily? Can you sat your house plants out side to get rain water and then bring it back in after the leafs dry off? Will I get bugs when I do that? I had another plant that had bugs my freind repotted it and when he took the dirt off the dirt had a big worm in it, So what was going on with that plant,repotted it and the plant died, I don't want to lose this plant

Answer
Hi YM,

The "fruit flies" are fungus gnats. The larvae of the gnats are what you see in the soil. As they mature, they develop wings and fly off to lay eggs in other locations that have decaying organic matter. The larvae were probably in the soil used in the nursery or from any soil you may have added. It takes a while for them to reproduce to the point where they become noticeable.

The winged adults only live for about a week before dying a natural death. So it is the larvae in the soil that need to be treated to interrupt the life cycle of these unpleasant critters. The larvae live in the uppermost portion of the soil where they feed on wet soil and decaying roots.

Remove and discard all loose soil that is not in direct contact with the roots. Do not replace this soil. This will eliminate many of the larvae. Then, add a thin layer of sharp builders sand to the surface of teh soil. You want to deprive the larvae of as much moisture as possible, so do not water your Peace Lily until it starts to wilt a bit and then give it less water than usual. The dryness and the sharp edges of the sand particles will dry and carve up the larvae. You should see a decline in the number of flying gnats within a week or two.

Don't leave your plant outside in the rain because it may get too wet. If your tap water is hard, use filtered or distilled water for your Peace Lily.

Replacing soil is never recommended because it damages the tiny root hairs that do most of the work. The worm does no harm, but it does indicate that the plant was grown by a nursery that cuts corners by using poor quality, non-sterile soil.

I have written articles on indoor plant pests and on Peace Lily care that I will email for free to you (or anyone else) who sends a request to me at [email protected].

Please let me know if any of this is unclear or if you have any additional questions.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

Visit my website at: A link to HorticulturalHelp.com