Assessing the impact of floral crop species and control strategies on TSWV/INSV population in commercial production Progress Reports – June 2001
ASSESSING THE IMPACT OF FLORAL CROP SPECIES AND
CONTROL STRATEGIES ON TSWV/INSV POPULATIONS IN COMMERCIAL PRODUCTION
James Moyer
North Carolina State University
Progress Report Year 1
07-01-2000 thru 06-30-2001
Industry Needs: Tomato spotted wilt virus (TSWV) and Impatiens
necrotic spot virus (INSV) are two closely related viruses, both transmitted by
thrips that continue to pose a major threat to the floral crop industry. There
are no chemicals available for control of plant viruses and vector control is
only effective when combined with stringent attempts to eliminate or reduce the
presence of the virus in the cropping area. As the vectors and the viruses have
extensive overlapping host ranges that include many of the floral crops being
produced, control of the TSWV/JNSV is largely dependent upon preventing either
the vector or the virus from entering the production cycle and managing prod
production to slow disease progress if and when the virus is present. Using
propagation stock previously tested for the viruses to reduce the risk of
introduction of these viruses has become standard practice over the past ten
years in many, but not all, floral crops. As it is impossible to reduce the risk
of introduction to zero, current research efforts are designed to provide tools
that will provide greater insight into control recommendations, improve
assessment of control strategies and to pinpoint potential sources of virus
introduction.
Research summary: This was year one of a new project that was
initially funded August , 2001. The primary objectives of the research grant
(3yr) are to conduct research on INSV to explain why INSV is the predominant
virus in the floral crop industry. To accomplish this objective we will
establish collaborations with growers throughout the US from which natural
isolates of INSV and TSWV can be collected and characterized. These analyses
will be on biological and molecular characteristics. The biological
characterization will provide information regarding differences in strains and
the molecular characterization will provide molecular markers or ‘signatures’
that can be used to identify natural populations of the virus. Once these
populations have been characterized they can be useful in providing insight as
to the origin of the virus infection. For example, whether the virus was
recently introduced into the crop from the field or has been in the production
cycle for a long time. It is also hoped that some indication of geographic
region of origin can also be determined.
This first year has been spent initiating the study. We now have a graduate
student dedicated to this work. She has initiated her graduate studies and begun
her research project to provide the molecular characteristics of different
populations. She has purified INSV so that new antiserum can be produced. She is
now developing protocols for TSWV and INSV analysis of natural populations. We
have also obtained several field isolates from diverse regions and locations:
For example, we now have or are being sent TSWV from field grown ranunculus
(CA); INSV from CaIIa Lily (CA); TSWV from Spain (field) and numerous TSWV and
JNSV samples from floral crops received at NC Plant disease clinic. These
isolates will be sufficient to develop and test protocols. Additional
collaborators have been identified as potential sources of isolates from the US
floral culture industry, Japan, Africa, South America and Europe. The student
was on state support during the past year but will be supported totally on this
grant in the coming year.
Progress has also been made on Objective 2. The goal of this objective is to
determine how specific floral crops and vector species influence changes in
viral populations. This research has only been initiated recently. Although
experiments have been initiated, we have no results to report at this time.
* To be received in early June
