Black olives browning

With the increase planting of black olives (Bucida buceras) in our area, a nuisance pest has come along with it – the bucida caterpillar.  Normally more abundant south of us, this moth has worked its way up to Charlotte County.  While black olives are not fully hardy in all parts of Charlotte County, they are a beautiful tree.   When a problem pops up on them, people start to take notice.

Normally black olives, especially the very popular cultivar, ‘Shady Lady’ are nice and green.  But in recent years, during April and May, the tiny caterpillars of the nondescript gray moth called Characoma nilotica,  begin to feed and cause some defoliation on black olives.  The caterpillars are so inconspicuous that they are often not even noticed until the damage is well underway.  The only time these caterpillars may actually “fly in your face” is when they are hanging by silken threads from the tree earning them the name “bungee caterpillars”.   They eat the flowers first and then progress to the leaves which gives the black olive a brown, haggard look.  As they complete their life cycle, they used clipped leaves to make hiding places to produce white cocoons and pupate.  These little white cocoons are fairly easy to see and are particularly distinctive. 

Now for the good news – the infested black olive will re-foliate and be back to new in four to six weeks!  The nuisance of these caterpillars is short-term and there is generally no lasting damage or stress.  As such, the need to manage or control these insects is often not necessary.  If you wanted to attempt a control effort, you would have to start monitoring earlier to detect the minute young caterpillars.  The use of the caterpillar insecticide  Bt or Bacillus thuringiensis could help reduce the  damage, but there would only be a small window of opportunity to make the application(s) as per label instructions. 

Regardless, the black olive tree is a nice addition to our landscapes – especially in coastal Punta Gorda and in protected microclimates in Port Charlotte.  A tiny problem like the bungee caterpillar should not discourage you as its damage is minor and the blemishes caused are not long-lived.  For more information on all types of insect pests, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf .

Resource:

Caldwell, D. (2008) “Black Olive” or Bucida Caterpillar (Characoma nilotica) a Nuisance Pest.  The University of Florida Extension Service, IFAS.