Expert: Mike Mascio - 7/24/2007

Question
We live in a very hot desert environment. (St. George, Utah)  This is our first year with container gardens.   Our zucchini is flowering but the leaves are turning brown.  We also noticed little black specs.  We sprayed.  Any helpful news would be appreciated.

Answer
Linda, leaves on most squash plants, including zucchini, will turn brown in extremely hot weather. Normally, they will still produce a normal harvest by sending out new vines until the plant has run its course.

To protect the plant from the heat, make sure you mulch around the plants with either shredded leaves or shredded bark. Mulch helps cool the soil and retain moisture. Also, supplement the watering by ensuring the plants receive at least 2" of water per week.

In regard to the black specks, these are most likely mites or flea beetles. You can spray them with either pyrethrum or rotenone. Both are organic insecticides that are very effective against insects, but non-toxic to humans. Attached are links to sites that sell these products.

http://www.gardensalive.com/product.asp?pn=8659&ss=rotenone
http://www.planetnatural.com/site/rotenone-pyrethrin.html

I hope this information helps. Please write again if I can ever be of assistance.

Regards,

Mike