pests and diseases Flashcards
what is the disease triangle
a disease can’t develop unless all corners of the triangle are favourable
- environment
- host
- pathogen
effect of net/spot blotch
straw is weakened but the main effect is a reduction in yield caused by flag leaf infections
loss per 1% flag leaf infection at the milky white stage is a 0.72%loss in yield
control of net/spot blotch
seed dressings
crop hygiene: deep ploughing/burning
resistant cultivars
foliar spray: expensive so used sparingly
what is the take all disease
root disease
can parasite over 400 grass species
control of take-all disease
rotation
destruction
control of perennial grasses
what are the main types of pest controll
- cultural control
- plant resistance
- insect pheromones
- and insecticides
what is involved in cultural control
making the soil or crop less favourable to the pest
includes cultivation
intercropping
crop rotation
burning/hygine
insect pheromones
trap and kill
mating disruption
grass grub is?
larvae that live in the soil and fees on roots of grass and clover
adults can severely damage orchard crops
control of grass grub
biological control- a bacteria causing milky disease
insecticide control- organophosphates
what is Porina
larvae/caterpillars also live in the soil but feed on foliage instead of roots
how to control Porina
natural control-viruses
insecticide control
one organophosphate and one insect growth regulator
