Insect infestation in gourds

Adrian Swain inquired about how to rid gourds of "burrowing insects" in
all life stages.

First, you need to positively identify the species that is infesting
your objects.  Without knowing exactly what animals that you are
dealing with, you cannot effectively design a control process that
will work. You can get help from your university entomology dept.,
the agriculture dept., and/or the county extention agent.

Next, I would suggest that you consider freezing as an effective
treatment for all life stages of what sounds like anobid or lictid
beetles.  Fumigation, from the information that you presented, was a
poor choice because obviously the fumigant did not penetrate through
the walls of the gourds!  If the objects have not recently been
exposed to low temperatures (i.e. below freezing) for a long period
of time; and the objects and their components can withstand
temperatures of -5 degrees F, then a double cycle freezing treatment
should work.  The objects must be wrapped in 6 mil polyethylene
sheeting or bags and allowed to sit at room temperature for several
hours after wrapping. They should be at equilibrium RH and not have
excess water content before freezing.

Then they can be placed in a freezer that can get to the target
temperature mentioned above.  This should be monitored with a
thermoprobe (Radio Shack sells indoor/outdoor thermometers with
probes for $15.00) that is placed inside the package.  The object is
left in the freezer for 48 hours; removed and placed in a
refrigerator (approximately 40 deg. F) for 8 hours, then placed back
in the deep freeze for another 48 hours.  I'm sure that other
conservators will suggest a single cycle at -30 degrees C for seven
days, but I have used this method ("double reduction") successfully
on similar objects and have continually obtained 100% kill rates on
all stages.  I would agree that thick pieces of wood need longer
freezing times to assure that the entire object is brought down to
temp., but lighter, thinner objects will chill faster and more
completely.

Please contact me off-list if you have any questions on this
treatment or need help with deciding if it is the correct treatment
for the objects.

Paul S. Storch
Objects Conservator
John and Martha Daniels Objects Conservation Laboratory (JMD-OCL)
B-109.1, Minnesota History Center

                                  ***
                  Conservation DistList Instance 11:22
                 Distributed: Friday, September 5, 1997
                       Message Id: cdl-11-22-002
                                  ***