Transcript Trap Crops, Indicator Plants & Banker Plants

Trap crops, indicator plants and
banker plants:
Tools for IPM in Greenhouse
Production
Elizabeth Lamb
New York State IPM Program
Coordinator for Ornamentals
[email protected]
www.nysipm.cornell.edu
All photos by E. Lamb except where otherwise noted
Indicator plants, trap crops and
banker plants provide additional tools
for managing pests in greenhouses
Indicator plants
• Indicator plants are usually species or
varieties that are particularly susceptible to,
or tolerant of, certain conditions
– Environment
• Ground ivy in shady lawns
• Salt tolerant species
• Phenology for insect development
– Gypsy moth egg hatch corresponds to the first bloom of
Eastern dogwood in Ohio
• Disease and insect presence
– Indicators are more attractive to insects than crop
Potato chunks as
indicator for fungus
gnat larvae
Virus Indicator Plants
• Diseases indicated
– Impatiens Necrotic Spot Virus (INSV)
– Tomato Spotted Wilt Virus (TSWV)
• Vectored by
– Western flower thrips
• Petunia
– cultivars Summer Madness, Super Blue Magic,
Calypso, Red Cloud
• Fava beans
– cultivar Aquadulce
Virus Indicator Plants
• Characteristics
– Very attractive to western flower thrips
– Feeding scars show up quickly and
infected lesions form quickly (2-3 days)
– Petunias do not serve as a source of virus
• Not true of fava beans but seed may be less
expensive
– Therefore must remove infected fava beans as soon
as possible
• Remove infected petunia leaves but plants can
stay
Blue attracts the thrips but
the plates aren’t sticky so the
thrips feed on the indicator
plants rather than getting
stuck.
Photos: Tina Smith, UMass Extension
Tomato
plant
Photo:
Graeme
Murphy
Tomatoes as indicator plants for whitefly in poinsettia
Trap crops
• Trap crops are most often used for insect
pest control
– Perimeter trap cropping in field vegetables
– Trap crops interspersed in greenhouse
ornamentals
• Characteristics
– Species or cultivar used needs to be more
attractive to pest than crop is
Perimeter trap
cropping of collards
for cabbage diamondback moth
Photo: T.J. Boucher, University of Connecticut
Other vegetable trap crop systems:
Hubbard squash for other Cucurbita - cucumber beetles
Cherry peppers for bell peppers - pepper maggots
• Methodology
– Trap crop must encircle other crop
– Control pest on trap crop as soon as it is seen
• Advantages
– Lower use of pesticide
– Maintains populations of indigenous natural
enemies
• Attractiveness as a problem?
– Will the trap crop plants attract more insects than
would have been there anyway?
While perimeter trap cropping can be used in the
greenhouse, it is more common to see the trap crop
interspersed among the crop plants
Some examples
• Whitefly in poinsettia
– Tomato
– Eggplant
• Thrips in chrysanthemum
– Gerbera
– Verbena
– Chrysanthemum - more susceptible
cultivar
For attracting western flower thrips, the trap crop is in flower before
the saleable crop
At all 3 distances from the release
point, the chrysanthemum plants
with open flowers were more
attractive to the thrips than plants
with foliage, buds or buds
showing color (crack buds).
Table from Buitenhuis, Shipp, Jandricic and Short,
Greenhouse Canada, September 2006, pp 10, 12
What factors do you need to
consider when using trap crops?
• Placement
– Near vents for pests moving in from outside
– Throughout crop
• Number
– How far does pest move?
• Stage of crop plant
– Flowering vs. vegetative
• Control on trap crop or not
– Chrysanthemum example - systemic control on
trap plants
Eggplant in gerbera crop
Banker plants
• Banker plants serve as a site for rearing biocontrol
agents in the greenhouse by providing them with an
alternative food source.
• The banker plants can consist of the same
crop/crop pest as that you are trying to control, or
can be an alternate host and prey
– Bird cherry aphid on wheat for green peach aphid control
– Greenhouse whitefly on eggplant for greenhouse whitefly
control
Banker plants for aphid control
• Bird cherry aphid does not infest plants other
than grasses but the parasitoid (Aphidius,
commonly) can easily more throughout the
greenhouse to parasitize other aphids
• Need a continuous supply of infested wheat (or
barley or oat) plants to provide an alternate host
when aphid numbers in crop decrease
• This system is being sold as a unit by biocontrol
companies or can be a do-it-yourself operation
Parasitized
aphids on wheat
banker plants
Grower with new pots of wheat in greenhouse and with aphid
infested wheat in cooler before placing pots in greenhouse
Banker plants dispersed in greenhouse
Note irrigation - this system
saves bench space for crop
and allows best maintenance
of banker plant
Old plants are left in
the greenhouse for
parasitoid to emerge
from parasitized aphids
Eggplant trap crop/banker plant
for whitefly on poinsettia
• New system not yet commercially available
• Eggplant is more attractive to white fly than
poinsettia
– Eggplant acts as an indicator plant, a trap crop
and a ‘nursery’ for biological control agents
– Pest populations on eggplant are inoculated
with parasitoids to provide beneficials for crop
Note
whiteflies
on
undersides
of leaves
Eggplants inoculated with Encarsia formosa for control of greenhouse
whitefly and Eretmocerus mundus for control of Bemisia whitefly
Eggplants interspersed in poinsettia crop
While this system
is used less
commonly, there
are indications
that it can aid in
the control of
whitefly in
poinsettia
Table from Osborne and Barrett, 2005, You Can
Bank On It, Ornamental Outlook, September, pp
26-27
Supporting information
• Lance Osborne, University of Florida
– http://mrec.ifas.ufl.edu/lso/banker/banker.htm
• You Can Bank on It, Ornamental Outlook, September 2005, pp
26-27
• Graeme Murphy, OMAFRA
– http://www.omafra.gov.on.ca/english/crops/hort/news/gro
wer/2004/07gn04a1.htm
• Trap Crops and Banker Plants - thinking outside the pest
management tool box
• Leanne Pundt, University of Connecticut
– http://www.hort.uconn.edu/ipm/greenhs/htms/tospov.htm
• Using Indicator Plants to Detect Tospoviruses