Subject: 1992 Biocontrol Annual Report
From: [email-masked] (Richard McDonald)
Date: Tue, 8 Jun 93 14:50:01 EDT

Biological Control Activities

     A.  Japanese Beetle

          Puparia of Istocheta aldrichi, a tachinid parasitoid of
          adult Japanese beetles, were overwintered in an
          environmental chamber, and released in the Azores in May
          in cooperation with Dr. Michael Klein of the USDA-ARS,
          Japanese Beetle Research Lab in Wooster, Ohio.  Also, in
          cooperation with Dr. Klein, attempts were made to collect
          the larval parasitoid Tiphia vernalis, in Caldwell County
          during the spring of 1992.  On May 21, 1992, just two
          adults were collected; these were held as vouchers.

          Further cooperative work with Dr. Klein led to foreign
          exploration for natural enemies of the Japanese beetle.
          A trip to China and Japan funded by USDA, ARS from June
          22 to August 6, 1992 allowed Drs. Klein and McDonald to
          collect several unidentified wasp species attacking
          scarab beetle larvae.  Some of these may hold promise as
          biocontrol agents of the Japanese beetle in North
          Carolina.  In Japan, some parasitic wasps that attack
          beetle grubs were collected.  These parasitic wasps are 
          currently held in NCDA quarantine and are being tested
          against the common grub species in North Carolina
          including Japanese beetle, Oriental beetle, green June
          beetle and June beetle.

          Drs. Klein and McDonald were also able to collect over
          400 Japanese beetle adults parasitized by I. aldrichi.
          The preferred habitat of the beetle and I. aldrichi is
          along mountain streams populated by Japanese knotweed,
          Polygonum cuspidatum.  The leaves of this plant are a
          preferred food for the adult beetles, and the flowers are
          an important nectar source for the parasite.  Most of the
          parasitized beetles were found on this plant.  One of the
          major pest weeds in the mountains of North Carolina is
          Japanese knotweed, and it hosts a large population of
          Japanese beetles.  Thus, a niche is available in North
          Carolina to introduce I. aldrichi.  It was also noted
          that the native climate of the areas that host large
          populations of I. aldrichi are very similar to climatic
          conditions found in the mountains of North Carolina. 
          Thus, the outlook to establish this parasitic fly in the
          mountains of North Carolina appears to be very promising. 
          A small number of I. aldrichi puparia (600) were released
          in Madison County along the banks of a Japanese knotweed-
          infested stream that has large populations of Japanese
          beetles; this site will be monitored for the presence of
          the fly during the summer of 1993.

          In addition, 8000 Japanese beetles parasitized by I.
          aldrichi were collected in Connecticut.  Beetles were
          returned to North Carolina, dissected, and approximately
          3500 puparia obtained and processed through the
          quarantine facility.  These puparia will be overwintered
          in an environmental chamber and will be released in the
          Azores in late spring of 1993.  This phase of Japanese
          beetle work is also funded by USDA, ARS.

     B.  Cereal Leaf Beetle

          Cereal leaf beetle, Oulema melanopus, is an introduced
          pest of small grains.  In an effort to reduce insecticide
          use and production costs to grain growers, a biological
          control program has been established to rear and
          redistribute Tetrastichus julis and Anaphes flavipes, two
          parasitoids of the cereal leaf beetle, into small grain
          regions of the state.

          Parasitoids are reared at several field insectaries in
          North Carolina.  Insectary sites were monitored for
          parasite emergence, synchrony between parasite and host,
          and percent parasitism.  Field days were held at the
          Piedmont Research Station in May for growers to collect
          parasitized cereal leaf beetle larvae for release into
          their small grain fields.  In 1992, T.  julis was
          redistributed into small grain fields in three counties.

     C.  Rosette Weevil

          The thistle rosette weevil, Trichosirocalus horridus
          (Panzer), a native of Europe, was released against musk
          thistle, Carduus thoermeri, in one site in Franklin
          County in 1992 (600 weevil adults per site).  Due to the
          weevil's feeding habits and life history, it was very
          difficult to detect for about three years after its
          initial release.  Two rosette weevils were recovered from
          a musk thistle plant at the Piedmont Research Station in
          Rowan County.  The nearest release was 60 miles southwest
          in Cleveland County.  Monitoring activities in Madison
          and Cleveland counties are continuing.  It is anticipated
          that the rosette weevil will establish and within 3-5
          years be numerous enough to be redistributed to other
          thistle-infested areas in North Carolina.  

     D.  Scale Predators

          During 1992, 211 adults of the imported Korean scale
          predator C. kuwanae (Coleoptera:  Coccinellidae) were
          collected from the insectary on the grounds of the NCDA
          BioControl Laboratory and shipped to cooperators in
          Georgia (N=35), Tennessee (N=33), Mississippi (N=73) and
          Florida (N=70).  Efforts to further distribute this
          predator within North Carolina were discontinued; surveys
          by APHIS during 1992 indicate that the insect is
          currently widespread within the state.

     E.  Azalea Lace Bug

          During the winter of 1992, studies were conducted to
          determine the oviposition capacity of overwintering
          female azalea lace bugs (ALB).  Studies were conducted 
          January 10 to February 14, 1992 in the laboratory and
          February 17 to April 20 in the field.  Females in both
          studies readily laid eggs, indicating an absence of a
          winter reproductive diapause.

          Ten nurseries that had ALB infestations during their 1991
          nursery inspections were re-inspected during the winter
          of 1992 to determine the effectiveness of the control
          measures taken and to determine the presence of adult
          ALB.  The nurseries were located in eight counties in the
          central Piedmont.  Adult ALB were found in six of the ten
          nurseries.  ALB eggs were present in all ten nurseries.

     F.  Flowerhead Weevil

          The thistle flowerhead weevil, Rhinocyllus conicus
          (Froelich), a native of Europe, was released against
          plumeless thistle, Carduus acanthoides, in Madison County
          in 1991.  The flowerhead weevil was also released against
          musk thistle Carduus thoermeri, in Cleveland County and
          Franklin County in 1992.  Surveys of the Madison County
          release site found that the weevil had successfully
          overwintered and had spread approximately one mile from
          the original release site. The release sites in Cleveland
          and Franklin County will be monitored to determine
          establishment of the weevil. It is anticipated that the
          flowerhead weevil will establish and within 3-5 years be
          numerous enough to be able to be redistributed to other
          thistle-infested areas in North Carolina.

     G.  Mole Cricket

          The mole cricket, Scapteriscus spp., causes a tremendous
          amount of damage to turf and pasture grasses in North
          Carolina.  In 1991, 196 puparia of the red-eyed fly,
          Ormia depleta, a parasite of mole crickets native to
          Brazil, were released in Brunswick County. Monitoring of
          the release site during 1992 did not detect any adults of
          the red-eyed fly; however, monitoring efforts will
          continue to determine if the fly can establish and
          overwinter in North Carolina.