Expert: Long Island Gardener - 2/20/2008

Question
I have wave petunias in baskets outside every summer. The last 2 years, some of them have what seems like a very small fly, green in color, on them. The fly seems to leave a white or black substance on the plant. In no time at all, the plant gets spindly and quites producing flowers and has to be taken down because it look so terrible. What would the problem be and how can I get rid of them ? I have tried ammonia water, sunlight soap and even malathion with no results.   
Thanks !

Answer
Malathion, Grant?  Tsk, tsk, no dinner for you tonight.  That Malathion is murder on people.  What were you thinking, man?  Get with the program.  That chemicals stuff is so '90s.  Antichemicals is the way to go.  Out with Malathion.

You describe an insect pest known as Whitefly, although yours seem to be Green instead.  Yellow sticky traps are very effective at collecting all kinds of flying insects.  You don't have to buy them --you can make them.  You need some YELLOW CARDBOARD or Index Cards, a few Paper Clips, a pair of Scissors and a product called TANGLEFOOT, used to deter pigeons from roofs and outside windows in the Big City.

Cut out an index-card-sized piece of the Yellow Cardboard.  [Note: This MUST be yellow!  White, Black, Blue, Orang, Green are NOT YELLOW.  This MUST BE YELLOW!]

Spread the Tanglefoot on the Yellow Cardboard/Index Card.  In the middle, punch a little hole and thread it with a Clip, then hang it off a branch.

It should be hanging near the soil.

That's where newly hatched Fungus Gnats pop and jump all over the place.  They will be stuck to your trap in no time.

You can't stop them from coming back, but you can catch so many that the problem is over for the season.  Try this system.  It works.  It's
just not permanent permanent permanent.

Thanks for writing.  Keep me posted; any questions, I'm here.