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Monday, August 17, 2015

Gluttons in the Garden

In between showers this morning (Yes, we have been getting some wonderful, cooling rain!) I stepped out on the deck to refill the hummingbird feeder.  The first thing I saw was a pile of  green pellets  littering the deck.
 If you grow tomatoes you are probably familiar with the sight, but for those of you who aren’t’ familiar, those pellets are frass, or the excrement of the tomato or tobacco hornworm.  This particular frass belongs to a  tobacco hornworm,  the same one, or the relative of  the one, that dashed my hopes of a decent tomato crop this year.

 I planted the  heirloom Opalka tomato seeds in  the Earthboxes on the deck with such high hopes, and  in June they definitely showed promise, as you can see here.
 Then, one morning I  looked out horrified.  My once bountiful, leafy, fruit laden  tomato plants  had been defoliated!  The scientific name for this particular hornworm is Manduca sexta. Manduca comes from the Latin word for glutton, a very apt description for this voracious eater!  There, at the base of the plants were the telltale pellets.  Hornworms are notoriously hard to  see because they are masters of disguise and manage to blend right in with the leaves and stalks of the tomato plant, but there they were-  chomping away. They have, over the last few years, become the bane of my tomato-growing existence. I pick them off and  dispatch them- I’ll spare you the gory details, but I don’t want to come back as a hornworm for I have done some despicable things to hornworms, maybe even worse than the crimes I have committed against ants.  Here  are some pics of the nasty little green devils at work. 

The damage  was almost complete by early August.  We managed to harvest a few tomatoes, but not many. Defeated once more, I left the plants there on the deck  for the remaining hornworms to finish off.  And finish them off they have- as evidenced by the  last remaining tomato in the last frame, and the fact that the pellets are much larger than they were  earlier in the summer. But I cannot find the hornworms this time. I have a feeling that they may be in the soil pupating. That  process is magical, and  a year or so ago we were able to witness the metamorphosis of a hornworm  into a  sphinx moth when I  inadvertently   dug up a pupa  while replanting the Earthboxes.  Here are some pics of what happened.The first pic is a close-up of the hornworm in  the larval stage.  See the horn on its  tail end? 

 This is the pupa  I dug up. I put it in a shallow  dish of  soil to finish the metamorphosis and hoped that it wouldn't dry out and die before making the transition.
Finally, we saw that the pupa case was beginning to split
Finally a moth struggled out,  shook off its wings and flew away to lay eggs and begin the cycle all over again.
The  hornworms that ate this year's tomato crop are probably the great grandchildren of  this one. And so it goes. . .
If you'd like to see  some much better pics and learn more about hornworms, here's a  really  nice and informative site from the University of Florida: Hornworms


Mim said...

I hate those things...I always fed them to my chickens!

Grace Smith said...

Our chickens got them as a special treat, too. I don't like them because of the damage they cause to my tomatoes, but they do turn into useful moths for pollinating plants,and the sphinx moth does pollinate our night blooming cereus, so I let some survive every year. It's hard to find a balance with nature sometimes.