L3 - environ on dis

Question 1

predict how disease will develop under a particular set of conditions - make ……. predictions by two ways?

Answer 1

Quantitative predictions

1. by research - evaluate understand increase management strategies
2. practical - recommendations for control max effectivness, less cost + eniron impact

Question 2

environmental modelling approaches are

ETAS

Answer 2

1. empirial/descriptive
   simple approach/correlation/regression know amount of incolulum + environmental conditions
2. theoretical analysis + synthesis
   syn - examine how weather effects each stage of the infection cycle

Question 3

Phytophthora infestans has been desribed by synthetic model
T has what effect on ? formation

Lesion formations op when?

Answer 3

T has what effect on sporangia formation

T<18 - indirect germ - for 6-8 zoospores
T>18 - direct - germ tube

model says indirect leads to more infections

20-25 degrees

Question 4

Phytophthora infestans infection depends on

Answer 4

leaf wetness
T
Disease resistance
blight proportion

Question 5

criteria for dis severity + impact

Answer 5

1. days till 50% infected
2. final disease severity
3. apparent basic infection rate, r
4. AUDPC

Question 6

can use synthesis model for growers to

Answer 6

indentify most susceptible and most resistant cultivars

Question 7

Yield Loss Modelling

Answer 7

yield loss proportional to AUDPC

can use to predict yield loss

Question 8

where has yield loss modelling recently been carried out

Answer 8

Bassimba 2017
circular leaf spot caused by Mycosphaerella nawae monitored yield loss to understand severity and effectiveness of fungicide.