In April 2010 and 2011 there were outbreaks of Cissusa spadix in
Clarke County, Georgia, United States.
In late April and early May, 2010, there was an outbreak of noctuid caterpillars in
Clarke County. These caterpillars spent the day in the leaf litter,
climbed host trees shortly after sunset (see
larvae climbing oak tree),
fed at night, and defoliated both large white and red oak trees
(Quercus alba and Quercus rubra).
They were reported at high numbers at sites in both the eastern and western parts of the county.
Based on caterpillar morphology, David Wagner, University of Connecticut, tentatively identified
this defoliator as either Phoberia atomaris or Cissusa spadix.
John Pickering collected larvae and reared 19 to pupae.
Of 18 pupae that were kept in an unheated room over winter, 10 Cissusa spadix and one parasitoid wasp (Hymenoptera, Ichneumonidae)
eclosed before 25 April, 2011. The first two moths eclosed on 4 March, 2011, the two days before wild Cissusa spadix
were photographed at lights.
Thus, this rearing confirmed that Cissusa spadix was the outbreak species.
At one wooded site in eastern Clarke County (275 Blue Heron Drive, Athens -- 33.888°N 83.297°W) adult
C. spadix were
photographed at lights between 29 March and 15 April, 2010 (see
adult C. spadix), as part of Discover Life's research to monitor nocturnal creatures.
P. atomaris were photographed at lights between 29 March and 5 April, 2010 (see
adult P. atomaris).
At 275 Blue Heron Drive in 2010, the first caterpillars were photographed on 23 April (see
caterpillars). The first pupae developed from collected caterpillars
on 3 May (see pupae and
Caterpillar numbers peaked between 30 April and 2 May. Numbers observed at night dropped off on 3 May, following a heavy rain storm.
Earlier in the 2010 season, there had been unusually large numbers of Eastern tent caterpillars,
Malacosoma americanum, at 275 Blue Heron Drive that defoliated Black cherry trees,
Prunus serotina (see caterpillar).
On 26 April, a Malacosoma americanum was photographed dead, apparently shedding NPV (see
dead caterpillar), as were others in the vicinity.
On 2 May, two C. spadix were photographed, also apparently killed by NPV (see
In 2011 a larger number of C. spadix adults were observed and photographed at 275 Blue Heron Drive than in 2010.
The first one was photographed on 6 March, 2011 and the last, on 11 April, 2011. However, as of 25 April,
fewer caterpillars have been observed at this site, although there is a widspread outbreak again in Clarke County.
Of interest is that there is a large build-up at lights in April 2011 of the
ichneumonid parasitoid that was reared from
a C. spadix pupa. These parasitoids were not observed in noticable numbers in 2010 at 275 Blue Heron Drive.
-- John Pickering, Jacqueline Mohan, Henning Von Schmeling, David Wagner, ... and anybody else whose wishes to contribute.