Pecan Diseases

Question 1

Where are pecans grown in the US?

Answer 1

South-Eastern USA

Question 2

What pecan disease is similar to a zinc deficiency?

Answer 2

Bunch disease

Question 3

What is the causal agent of pecan bunch disease?

Answer 3

phytoplasma

Question 4

How is pecan bunch disease naturally spread?

Answer 4

unknown

Question 5

Where is bunch disease phytoplasmas located in the pecan plant?

Answer 5

Phloem only

Question 6

Can pecan bunch disease be cultured in the lab?

Answer 6

No

Question 7

What insects transmit pecan bunch disease?

Answer 7

leafhoppers
treehoppers
psyllids

Question 8

What symptoms does pecan bunch disease show?

Answer 8

witches broom

Question 9

What is the easiest way to diagnose pecan bunch disease?

Answer 9

affected limbs shoot earlier in the early spring (7-14 days)

Question 10

How is pecan bunch disease controlled?

Answer 10

removal of infected shoots

Use Stuart as a cultivar

Question 11

What is the single most important pecan disease?

Answer 11

Scab

Question 12

What regulates the severity of pecan scab disease?

Answer 12

frequency of summer rains

Question 13

What is Fusicladosporium effusum?

Answer 13

pecan scab

Question 14

Where does pecan scab occur on the plant?

Answer 14

leaves, fruit shucks, green twigs

Question 15

What part of the pecan plant is most susceptible to scab?

Answer 15

young tender tissues

Question 16

What are symptoms of pecan scab?

Answer 16

small black spots on lower leaf surface

Question 17

When is pecan scab most damaging?

Answer 17

on shuck infections between fruit onset and shell hardening

Question 18

When does pecan scab secondary white fungal growth occur?

Answer 18

Late august

Question 19

What do severe infections of apple scab result in?

Answer 19

fruit death

Question 20

Where does pecan scab overwinter?

Answer 20

on tissues infected the previous year

Question 21

Are inoculum in the tree or on the ground more important for pecan scab?

Answer 21

in the tree

Question 22

When does the release of pecan scab conidia peak?

Answer 22

late morning hours

Question 23

How many hours of wetness is needed for significant leaf infections of pecan scab?

Answer 23

12

Question 24

How can pecan scab be controlled?

Answer 24

resistant cultivars

fungicides

Question 25

How can resistance to fungicides be avoided?

Answer 25

Use multiple fungicides with more than one mode of action
Apply as a preventative
Minimize the number of applications