Monday, June 30, 2014

Controlling Squash Bugs

Pest Patrol:  Squash Bugs


This is everybody’s worst pest and the one I get the most questions on- the dreaded squash bug.  Infestations will make even the most committed organic gardener want to reach for chemicals.  However both organic and non-organic people seems unable to win their battle against this insects.  I've heard a lot of people says they are just not planting squash this year.  Sad to say this will not do the trick.  They will come back the next time you do plant so you need a more consistent effective plan.  The key to conquering is consistency. 
You must know your enemy if you want to defeat it.  So a lesson on the life cycle of the squash bug is essential.  The adults overwinter in garden debris, under dirt clods and other protected areas. They lay bronze colored eggs on the underside of squash and pumpkin leaves. In our areas we can have two maybe 3 generations.  The key to conquering is recognizing the squash bug in the nymph stage.  It may be greenish, grey, or black and is much smaller than the adult. (I will put pictures on the blog) It will molt 5 times before becoming the dreaded creature you recognize.  They are easily controlled as nymphs and very difficult to control as adults.  Most insecticides are not very effective on the adults. They have very few natural predators because of the odor they put off when squashed.
So what is the plan of attack? Consistently monitor for eggs and adults. Crush eggs or cut off. Squash adults or get a shop vac and suck up adults or throw them in a bucket and feed to your ducks. They love them. 


 It's been helpful to me to follow a preventative spray program.  Every 2 weeks in a 1 gallon sprayer put 2 Tbs Neem, 4 Tbsp spinosad, and a 1 1/2 cups of kaolin clay.  I spray this on squash, pumpkins, cucumber, and melons, everything in this family.  If I see any nymphs or adults I add Pyrethrin.  Pyola is the only organic form of pyrethrin I have found.  It's available at Garden's Alive. It's mixed with an oil which also helps suffocate eggs.  Some formulas add additives or use a non-organic form of pyrethin. This can be sprayed early morning or evening (to avoid pollinators) every 3 days when the bugs are present. I grow a lot this insects favorite crops and refuse to lose the battle.  The key is consistency.  You have to check for eggs and spray on a regular basis and then you not the squash bug will enjoy your harvests. I hear a lot of, "I sprayed" but after learning about this pest you can see that one spray is not enough.  The key to getting rid of a pest is knowing its life cycle and when it is most vulnerable and attacking then.  Insecticides do not kill all insects at every stage.  The key is applying them when the pest is most vulnerable and when the insecticide is designed to kill.


So what's does each of these sprays do in your arsenal do?  Neem will kill the eggs and nymphs it is also a fungicide.  It must be ingested to cause damage so it doesn't harm beneficial insects.  It does not immediately kill the nymphs but interferes with their ability to molt so they die. Spinosad is a broad spectrum insecticide that kills on contact and when ingested by overexciting the nervous system.  It is toxic to bees if sprayed directly on them.  So don't spray when the pollinators are out. It is not toxic when dried. Not sure how effective it is on squash bugs but great for other pests.  You can leave this out if your only focus is the squash bug.  Kaolin clay is a deterrent not only to squash bugs but grasshoppers and other pests.  They prefer a plant without a sickly clay to munch and crawl around on.  Pyrethrin is a nerve toxin and does kill immediately but must make contact in order to do its job.  There is no point in spraying it if you have no pest to kill.
Other helpful hints.  Plant squash late.  When the adults emerge to lay eggs there is nothing to lay on.  Also clean all debris out of the garden at the end of summer.  Leaving plants in the garden over winter is a perfect squash bug condo to help them survive the winter.

Preventive Spray:  Every two weeks use on all members of the cucurbite family

Spray in evening when temperatures cool down and pollinators aren't around.

Mix in one gallon sprayer with water
2 Tbsp Neem Oil
1 1/2 cups of Kaolin Clay
4 Tbsp of Spinosad (optional)

Spray when nymphs or adults present:

Mix in one gallon sprayer with water
2 Tbsp of Neem Oil
1 1/2 cups of Kaolin Clay
Organic pyrethrin
4 Tbsp of Spinosad

You can respray in 3 days with just the Neem and Pyrethrin

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