ROSE - SHEET 466
Cut Rose Biological Control Program
This program works best with a new planting or if started in fall or winter when pest
levels are low
PEST PEST LEVEL BIOLOGICAL INTRODUCTION RATES
Thrips low (less than 5/card/week) Cucumeris 500 Cu.(Bulk)/m.sq./every 2 weeks
Cucumeris 1 SR Bag/m.sq./every 4 weeks
check flowers too, if more than 1thrips/flower continue cucumeris treatments .
Fungus Gnat low (less than 5/card/week) Hypoaspis 50/m.sq/once
check cards weekly if gnat numbers, increasing treat with treat substrate with nematodes or Bti .
Spider mite low (1-5/mites/leaf/a few plants) Stethorus 100/infested spot/weekly/3 times
Also add: Persimilis 2-3/m.sq./weekly/until
established
Also add: Fallacis 2/m.sq./weekly once
high (+5/mites/leaf/many plants) Stethorus 100/infested spot/weekly/3 times
Also add: Persimilis 20/m./hot spot weekly/established
Also add: Fallacis 4/m.sq./weekly/2 times
Also add: Feltiella 250/infested spot/weekly/4 times
Aphids preventive (no aphids found) Aphidius 0.15/m.sq./week/every 2 weeks
low (a few leaves with aphids) Aphidius 1/m.sq./weekly/3 times
high (many leaves with aphids) Aphidoletes 5-10m.sq./weekly/3 times
Also add: Harmonia 100/hot spot/3 times .
Whitefly low (less than 10/card/week) Encarsia 2/m.sq./weekly/until established
High (more than 20/card/week) Delphastus 20/m.sq./hot spot/weekly/5 times
High (temperatures 24C+) Eretmocerus 6/m.sq/hot spot/weekly/4 times
Cabbage Looper as soon as moths are detected Trichogramma 10-20/m.sq./weekly
Note: Biological control should not be attempted without a program of weekly
monitoring to assess pest and beneficial status. This should include the use of yellow
sticky traps (use a minimum of 20 traps/ha or 10 traps per greenhouse) and leaf
sampling, flagging of hot spots and recording of results on a greenhouse map. A
minimum of one hour a week per acre (2 hours/ha) should be spent on monitoring
activities especially when first setting up a program.
Western Flower Thrips: Research in roses has determined that 25-50 thrips per yellow
sticky card per week means that there is an average of one thrips per flower. Thrips
numbers above this result in visible flower injury(Casey et al, 1999). As Cucumeris can
only feed on the youngest stages of thrips it is important that a population of Cucumeris
is present throughout the crop at all times. See rates on table above.
Two-spotted Spidermite: On bent cane rose plants most mites are found near the crown
where the cane is bent and this can be used as a control strategy by spraying this area
with a compatible spray if necessary while still allowing predators to build up on other
plant parts without affecting the flowers. The predatory mite, Fallacis will establish on
roses and can assist with mite control as it tolerates a wider temperature and humidity
range than Persimilis. Fallacis is also resistant to most pesticides. The mite eating
ladybeetle, Stethorus is also very effective at detecting individual mite colonies and can
improve control of spider mite.
Aphids: The main species of aphid found in roses is the Green Peach Aphid but other
species such as the Cotton Aphid and Potato Aphid can occur so these should be
ROSE - SHEET 466
identified to select use the correct species of parasite. Aphidoletes and Harmonia will
feed on all species of aphids.
Whitefly: As soon as whitefly are detected on monitoring cards or on the plants begin
introductions of Encarsia and Delphastus. See rates above.
Fungus Gnats: To prevent fungus gnats from building up apply a preventive
application of Hypoaspis early in the season. See rates above.
Nursery and Indicator Plants: The use of greenhouse pepper plants as indicator and
nursery plants is highly recommended. Start with a few plants along the walkway
trained up support posts. Greenhouse pepper or eggplants are available from
propagators and are attractive to aphids and most pests and can be used to release and
build-up populations of biological control agents which will migrate on to the main
crop. Nursery plants also enable greenhouse staff to clearly observe and learn the life
cycles of many parasites and predators and act as an early warning for pests as well as
detecting any problems with beneficials establishing.
Pesticides: Check the compatibility list before using any pesticide as most are very
harmful to beneficials. Remember that the pest is also the food source to multiply the
number of biological control agents. A low level of pests is not necessarily a bad thing if
biological control agents are also present. Fungicides usually cause less disruption than
insecticides or miticides. Reduce the use of sulphur vaporizors (1Kg/ha) to 2 or 3 nights
a week or sprinkle the sulphur along the main pathways to vaporize to minimize harm
to predatory mites. Agral and most other spray adjuvants or spreader stickers are
harmful to beneficials but 0.25%Magnesium Sulphate (2.5g/liter) works as well for this
purpose and is harmless. If soap sprays are used, rinse plants with water 15-30 minutes
after spraying and never apply soap on sunny days.
Pests and Chemicals Usually Safe for Biological Control Agents (call bio-supplier before use)
Pest Chemical, Rate and method of use (follow label for greenhouse use and precautions)
mildew Sulphur (1Kg/ha/bi-weekly) vaporizers or sprinkle powder onto pathway to vaporize
spider mites Vendex 50W (0.50g/L of water) spray with high volume sprayer
aphids Insecticidal Soap (25ml/L of water), high volume sprayer
thrips Insecticidal Soap (25ml/L of water), high volume sprayer
whitefly Insecticidal Soap (25ml/L of water), high volume sprayer
caterpillars Bt (follow label)
