L5 -Fungicide res

Question 1

metalaxyl is a

used to treat

Answer 1

acylalanine

potato late blight, Phytophthora infestans

Question 2

metalaxyl history of res

Answer 2

78- used
80 - failure to control
81 - metalaxyl withdrawn
85 - used but only in mixuture (eg. maozeb)

Question 3

P. infestans evolved res to metalaxyl mainly due to

Answer 3

mix of sensitive and insensitive populations by sexual reproduction ?

Question 4

p. infestans current status?

Answer 4

stabalised res at 50-60% 2009 both sen and insensitive strains present in pop

Question 5

how to prevent pop to complete res (1-3)

Answer 5

1. use fungicide early in teh season and use protectant later on
2. dont use curatively
3. dont use on potatoes grown for seed

Question 6

what is the aim of forecasting and decision support systems

Answer 6

predict occurrence of disease to

1. minimuse fungicide use
2. max effectiveness of fungicide

Question 7

what are DSS

Answer 7

decision support systems - comp based technology to help overcome problems under complex uncertain conditions

Question 8

what are the requirements needed for using DSS

VSAA

Answer 8

variation in severity

sufficient biological data

accurate forceasting

appropriate management tech

Question 9

3 types of forecast based on

AFO

Answer 9

1. availability of initial inoculum
2. fav environ for dis development
3. observations on disease incidence

Question 10

what forecasting systems are used for Potato Late Blight based on environmental conditions?

has recently recently been modified

Answer 10

SMITH period
req: 2 x consec days T>10 RH>90% for 11h

• said to be for too long, lower threshold -

HUTTON Criteria
req: 2 x consec days T>10 RH>90% for 6h

means more people ‘at risk’ but still will be beneficial as more people using the system and less prophytical spraying

Question 11

What system uses weather and combines two older systems

what results does it gives

Answer 11

BliteCast
USA

combines

1) Fav days - T not too high +suff rainfall
2) severity values - calc

Tells you to:
no spray 
warning 
5 day spray 
7 day spray

Question 12

what is SIMCAST

Answer 12

late blight forecasting systems
work out exp. dis development blight units on the basis of weather + last spray

takes into account dis res

Question 13

what is BlitePro

Answer 13

combines BliteCast (start spraying) and SIMCAST (schedule spraying)

Question 14

What commercial system is used a lot

Answer 14

Plant Plus
evidence shows 20% reduction in spraying
- effectiveness :)

Question 15

if a plant is subjected to >1 insect/pest then what method is appropriate?

Answer 15

Intergrated Management

• combine diff control methods
• integrate sys to deal with diff pests

Question 16

Example of integrated management for major company

Answer 16

Cambell soup
used TOMCAST
90% reduction in synthetic insecticide use
50% reduction in fungicide use

provide incentives !

Question 17

another example of potato late blight DSS

Answer 17

VNIIFBlight

VNIIFBlight

Fillipovv 2015