2103 - Plant Pests Flashcards
What is a Pest?
A multi-celled Organism belonging to the Animal kingdom that has the ability to attack and cause damage to any part of a plant.
Pests can be vertebrates or invertebrates.
Pest use the plant for food or shelter.
Common RHS Pest list
Rabbits Deer Pigeons Cabbage White Butterfly Buttefly Larvea Black Bean Aphid Peach Potato Aphid Two Spotted Spider Mite Glasshouse Whitefly Vine Weevil Slugs, Snails Potato Cyst Eelworm
Damage done / Control - Rabbits
Dig Holes, Strip bark from trees, eat crops
Breed in Spring, bulk up quickly, rapidly multiply
Controls:
Rabbit Proof Fencing (Cultural)
Hunting (Physical)
Damage done / Control - Moles
Dig through Lawns, leave big mound of soil (mole hills)
Most common in Hearty Loam Soils
Controls:
Humane Traps, check twice a day (Cultural)
Physical barriers
Smokes
Ultra-Sonic deterrents
Dig up tunnels and remove pest (Physical)
Damage done / Control - Deer
Eat Leaves, shoots and stems up to a level hey can reach.
Controls:
12ft fence
Culling / Hunting
Damage done / Control - Pigeon
Leaf and Crop damage
Controls:
Netting
Hunting / Shooting
Insect body parts (grasshopper)
- Head
- Thorax
- Abdomen
- Front wing, Hind wing
- Spircales (breathing/gas exchange)
- Invertebrates have an Exoskeleton
Points of Entry for Insecticide
Surface insecticide - for chewing insects
Translocated insecticide - sap sucking insects
Contact insecticide - (fatty acids) Block up Spircales
Insect Growth - Incomplete Metamorphosis
3 stages:
Egg, Nymph, Adult
Nymph stage resembles the adult. There can be several Nymph stages with growing and shedding of the Exoskeleton.
Nymph = Juvenile stage, growing not capable of sexual reproduction
Insect Growth - Complete Metamorphosis
4 stages:
Egg, Larva, Pupa, Adult (Butterfly)
The Larval stage is usually characterised but ravenous foraging, pupa by inactivity.
Classic example:
Egg, Caterpillar, Cocoon (chrysalis), Butterfly
Types of Insect Damage
- Sap Sucking (Aphid)
- Rasping (Slug)
- Chewing (Adult Vine Weevil)
Sap Sucking damage and control
Sap sucking insect, Use mouth parts (Stylet) to access sap in the plant. resulting in:
- Loss of Vigour
- Stunted Growth
- Distorted Foliage and Shoots
- Disease Transmission
Chemical Control - Translocated Insecticide.
Enters plants Phloem, transported around the plant, insect eats it and dies.
Sap Sucking - Black Bean Aphid
Black Bean Aphid
Incomplete Metamorphosis
Egg, Nymph (series of instars), Adult
Aphid eats Phloem sap, their waste matter is Honey Dew which encourage Ants, who will then protect the aphid colony. Honey Dew encourages mould.
Sap Sucking - Black Bean Aphid life cycle
Eggs are laid in crack, stems and twigs. Eg. Sambucus nigra or Euonymus europaeus - Spindle
Eggs hatch in Spring, wingless female feed on host plant.
Winged Males produced shortly after which fly to summer host plant. Typically Broad Beans, and Dahlias
Adults produced in late summer, fly to winter host and repeat the life cycle.
Sap Sucking - Black Bean Aphid Damage
- Stunted Growth
- Distroted Growth
- Reduced photosynthesis due to sooty moulds
- Secondary viral infections