Monday, May 30, 2011

Know thy enemy

  It has been a beautiful week, more like summer than spring-- temps in the 80's,  hot and humid.
Heavy dews in the morning have watered my new seedings more gently than I ever could. With the heat and the burgeoning garden come many hungry insects, and the battle over the garden begins again.
  Cultivated vegetables have been interbred for many generations to produce big, tasty foliage and fruit- tasty to both mammals and insects. I can fence to keep out the mammals, with a little help from Sol, but the insects are a more complicated problem. 
  I don't spray my gardens with chemical pesticides.  Just a few years ago, everyone did. I have a companion book from PBS's 'Victory Garden' TV show from the 1980's which advises routine weekly spraying of many crops with chemical pesticides.  There are several reasons I don't, including concerns about what pesticide residue can do to my health. But I also don't use chemical sprays because they are expensive, and in my small garden I'd rather save the money and invest some time.
  I visit the garden every morning and afternoon, and examine the plants.  I  turn over leaves to look for eggs, I pull weeds and thin seedlings, I pick a few things to eat.  I know my garden well, so I notice quickly if things change.  
  When black aphids appeared on the fava beans last week, I looked at all the growing tips to gauge how many there were-- the plants can handle a modest infestation without much damage. I noticed both daddy-long legs and ladybugs eating the aphids.  If the infestation gets too heavy for these insect predators, I  may wash the aphids off with water, and monitor.  Finally, if I decide favas always have major aphid problems, I'll stop growing them and plant a different bean next year.
  I saw a new insect on the potato plants yesterday, while I was picking off and crushing scale bugs.  It was small and gray, and had a predatory stance, so I didn't try to kill it. I'll go online and try to ID this new insect, so that the next time we meet I'll know for sure whether it is a friend or foe.
  I know cucumber beetles are the enemy.  I have never grown cucumbers, but every summer I wage war with these colorful, zippy black and yellow striped beetles.  They prefer to eat things in the cucumber family (which includes many squash plants, which I do grow), but will nibble on many other plants. 
   I have gotten very good at stalking cucumber beetles on cool summer mornings. I called them zippy because they are very good fliers, and will zip out from under my crushing fingers in the heat of noon, but in the morning they are as slow as college students.  I often find several of them snoozing the morning away inside squash blossoms, and gleefully crush them by squeezing the flower between my fingers.  Unchecked the cucumber beetles will eat leaves to the ribs, but they are even more dangerous as carriers of a nasty fungus that can rot the leaves they barely nibble.  Last year I planted a zucchini called 'Tigress" which was touted as resistant to this fungus, and they did well.  This year I am spreading the squash out around the yard, even in the flowerbeds, in the hope that cucumber beetles won't find them all, or at least, not too early in the summer. 
 And then there are the caterpillars-- cabbage worms, tomato hornworms, the awful army of winter moth caterpillars. For them I have a weapon that is not chemical, but bacteriological-- BT, which when sprayed on a leaf and then eaten by a caterpillar, slows and stops them eating, finally killing those that eat enough. Once again, there is no outright victory, because some damage is done, but I get most of the produce and the bugs get a little. I can live with that.