Predators, Pestilence and Pelargoniums

by Victoria Shepard


                    aphids                            white flies                                 ^   budworms   ^                                     Geranium rust 

I listened in abject horror as one of the key speakers at a garden club meeting detailed the painful closure of her commercial pelargonium nursery due to continuous whitefly infestation.  As anyone knows who lives to grow pellies (like me), reliable sources are significantly less plentiful than albino pigeons.  There is an overabundance of poisons ready and able to eliminate such pests and diseases, create undesirable mutations in your offspring and poison the family pets.   Based on 10+ years of growing and selling geraniums, I have a few suggestions that have truly helped me reduce whitefly, aphids, budworms and the dreaded rust.  And they are easy and relatively safe. 


For the sucking bugs like aphids and whitefly, I recommend worm castings sold under the name “Worm Gold”.  For you visual learners, there is a large, yellow worm on the bag holding a tulip, or something.  Worm castings are also a fertilizer so they feed your plants.  In a four-inch pot, I add about two tablespoons to the soil and then water.  Larger pots need more worm castings.  It reapplied every 4 months.  A friend dug worm castings into her borders, but did not see a reduction in whitefly activity.  It seems that worm excrement needs to be contained and concentrated in a pot so the plant has continuous and easy access in order to enjoy the benefits.  


Lets move on to budworms.


According to the Delta Farm Press which provides “timely and reliable agricultural information” for the southern portion of our country:


“Seven years of hiding must have been enough for

Mid-South tobacco budworms.  In 2002, the pest returned

 to the region's cotton fields with a vengeance...”.   


This bud worm scenario does not have to relive itself in your backyard.


 I recommend spinosad, a substance which is added to water and then sprayed on plants.  It is reported that a scientist on vacation in the Caribbean found the bacterium in an abandoned rum factory.  The substance was tested on budworms and found to be successful.  The most common brand in Southern California is “Monterey Garden Insect Spray”.  Bonide Products carries spinosad in its “Captain Jacks Dead Bug Brew.”  The budworm ingests the mixture; its nervous system goes haywire; it stops eating and dies one to two days later.  It should be applied every seven to fourteen days.


The other condition that I encounter every rainy season is geranium rust, which is actually a type of fungus. When there is moisture in the air, it manifests as raised brown rust colored bumps on the underside of zonals and spreads very easily through invisible, airborne spores.  The only positive aspect is that I can run through my garden with outstretched hands yelling, “There’s a fungus among us!”   However, that does nothing to alleviate the problem.   


There are various benign oils on the market that can be mixed with water and sprayed on the plants to smother the rust.  This has not been terribly successful for me.  I have found that limiting the amount of zonals I grow and cleaning out my greenhouse every spring with a mixture of neem oil, water and detergent has eradicated most of the problem.   Neem Oil is extracted from a tree native to the Indian subcontinent, so I feel confident that it will have no ill effects on my health unless I drink it. 




© 2010, Central Coast Geranium Society (CCGS )