Glossary Terms
Glossary Terms
Agdia, Inc. - Agdia is a diagnostic testing company that sells tospovirus detection kits for use in greenhouses and reagents for laboratories that use ELISA. Agdia also provides virus and other pathogen screening in their laboratories. For more information about Agdia their World Wide Web site is http://www.agdia.com. The address is Agdia Inc., 30380 County Road 6, Elkhart, IN 46514, phone 219-264-2014, Fax 219-264-2153.
bioassay- Use of the reaction of live plants in testing for virus, in contrast to methods using serology.
Bioreba Ag- This company sells reagents for laboratories that use ELISA tests for TSWV, INSV and Tospovirus-Broad Spectrum, as well as other plant pathogens. The USA distributor is BIOREBA Inc., 3702 West Sample Street, South Bend, Indiana 46619. The phone is 219-287-3788, Fax is 219-288-9363.
blight - A disease symptom that describes withering of above ground plant parts that usually progresses rapidly. Blight may be used for specific plant parts, for example leaf blight.
bronzing - A disease symptom in which plant cells, usually on the upper leaf surface, are damaged and the leaves appear shiny and brownish.
certified transplants - Plants that are produced under the guidelines of an organized program to ensure apparent freedom from injurious insects and diseases.
chlorotic (chlorosis) - A yellow, or pale green, condition of normally green tissue due to low chlorophyll levels. Chlorosis may be caused by nutrient deficiencies, low light conditions and plant diseases. Chlorotic tissue is a common symptom of virus infection.
color break- A symptom in which there are streaks of white or other colors in flower parts, usually petals. (Also called flower break.)
concentric ringspot - A symptom typical of some plant viruses in which a yellow or necrotic spot is surrounded by rings of tissue that are also yellow or necrotic. Also sometimes described as a thumbprint or bull’s eye pattern.
corm - A swollen underground stem that serves as a propagative structure in Crocus, Gladiolus, Cyclamen, and other plants.
ELISA- Enzyme Linked Immunosorbent Assay is a type of serological test that can be used to test for plant viruses and other plant pathogens.
epinasty - A downward bending of flower parts or leaves. Epinasty is different from wilting in that the tissues aren’t suffering from lack of water, but are misshapen from uneven cell growth on one side of the plant part.
flower break - see color break
Home and Garden Information Center (HGIC) - The University of Maryland Home and Garden Information Center provides answers to gardening questions for the citizens of Maryland through an 800 number staffed by trained Master Gardeners and extension specialists. The number is 1-800-342-2507.
host range - The plants that are attacked by a particular pathogen. Plant viruses are typically specific to a few host plants (narrow host range) but tospoviruses (INSV and TSWV) has a very wide host range with many different plants susceptible to attack.
impatiens necrotic spot virus (INSV) - Impatiens necrotic spot virus is a member of the tospovirus group and was first called TSWV-Impatiens. In 1991, researchers determined that this thrips-transmitted virus commonly found destroying impatiens, cyclamen and other greenhouse crops, was distinct from TSWV (not just a special strain) and named it INSV.
indicator plants- Plants that react with characteristic symptoms are one of the most reliable ways to detect a virus problem. Indicator plants, such young petunia plants, or fava bean seedlings, may be placed throughout a greenhouse range to monitor for the spread of tospovirus by thrips. If thrips feed on the leaves and spread virus, necrotic spots result. Indicator plants are also used in plant virology to indicate if a virus is present in a plant by grinding sample leaves then rubbing the extract onto test plants such as cucumber seedlings, Nicotiana, tomato and beans to see if lesions, mosaic or other symptoms result.
integrated pest management (IPM) - IPM is a system that uses monitoring pest and environmental conditions and using the best combinations of pest control options such as sanitation, biocontrol, and pesticides to prevent unacceptable lines of damage.
Maryland Department of Agriculture, Plant Protection & Weed Management Section- The Plant Protection and Weed Management Section of the Maryland Department of Agriculture is based in Annapolis, with field offices in Cheltenham, Riverdale and Salisbury. The Section serves Maryland Agriculture through programs including Plant Certification & Virus-free Plant Programs, Nursery Inspection and Licencing, Apiary Inspection, Pest Survey, IPM and Biocontrol, and Entomology and Plant Pathology Laboratories . For more information call 410-841-5920.
mosaic- A pattern of light green and dark green, or green and yellow, patches in a leaf that may be due to virus infection.
necrotic- Dead tissue,usually brown or black or sometimes papery tan.
necrotic spots- Distinct dead spots, for example, brown or dark brown areas of dead cells in a leaf that are brown or dark brown.
necrotic ring- Dead tissue that is in a circular pattern with normal tissue in the middle.
necrotic vascular system- Dead tissue in the vascular system of a plant, seen for example by slicing into a root or stem and looking for brown streaks.
plant virus - A parasite that is subcellular, composed of nucleic acid and protein, and is transmissible. Plant viruses replicate only within host cells. Plant viruses are typically named after the plant they are discovered in and the major symptom that results, for example tobacco mosaic virus (TMV).
ringspot - A circle of tissue that is yellow, brown, or darker in color from the center tissue. Often ringspots are a circle of brown on a leaf with green in the center.
serological tests- Diagnostic methods that are based on specific antibody-antigen reactions to determine if a substance or pathogen is present. One example is ELISA.
stem necrosis - Black areas on stems, usually in an elongated oval or circle or band.
sticky cards- Sticky cards are a monitoring tool for insect pest levels in plant growing areas. Typically blue or yellow, the cards have a very sticky surface that traps thrips and other insects for regular tracking of pest levels.
stunting - Smaller than normal plant size. This symptom may go unnoticed unless healthy plants are available for comparison.
terminal bud death- Death of the growing point of a shoot, often including surrounding leaves and stems.
thrips- Thrips are tiny (1/16th of an inch) winged insects that feed on plants by sucking sap from cells of leaves and flowers.
tomato spotted wilt virus (TSWV) - Tomato spotted wilt virus was first discovered causing wilt and spotting of tomatoes. The virus is thrips-transmitted and can infect a range of plants including tomatoes, peppers and peanuts usually causing losses in field plantings. The “tospovirus” group name is based on tomato spotted wilt virus.
tospoviruses - A group of plant viruses that are vectored by thrips. Two well known members are tomato spotted wilt virus (TSWV) and impatiens necrotic spot virus (INSV)
transmission- The movement and infection of disease agents, for example thrips transmit tospoviruses and cause new infections throughout a greenhouse crop.
University of Maryland Cooperative Extension Service- The University of Maryland is the land grant institution in Maryland and is home for the Cooperative Extension Service. With extensive educational and scientific research programs the Service provides growers and other citizens of Maryland current horticultural advice and training through such programs as Total Plant Management, Master Gardeners and the Home and Garden Information Center.
vector - An organism that carries a pathogen to a plant. Aphids, nematodes, thrips and whiteflies are common vectors of plant viruses. Only thrips vector tospovirus.
viruliferous - A term used to describe a vector that has acquired and carries a virus, and can transmit the virus to a healthy plant.
virus reservoir - Plants that may harbor a virus without obvious symptoms. Weeds are often virus reservoirs.
yellow rings - Circles of yellow in a green leaf. Also called chlorotic rings.
wilt- A collapse or drooping of leaves and shoots that may be caused by lack of water, excess fertilization or disease.
vascular system - The conductive system in plants, comprised of xylem and phloem, in which water and nutrients move.