| AFFECTING LEAVES: |
|
CONDITION |
CAUSE |
 |
Yellow,
curling leaf margins, wilted plants; flowers and pods drop. |
Potato leaf hoppers
|
|
Yellow,
distorted new growth. |
Tarnished plant bug
(Lygus pratensis)
|
|
Yellow
leaves, slow growth |
Nitrogen deficiency
|
|
Curled,
yellow, withered leaves |
Bean aphids, Bean mosaic, or Curly top
|
|
Small
reddish-brown specks, especially on leaf undersides; leaves yellow and
drop |
Rust
|
|
White,
stippled leaves, which later become bronzed, stunted growth |
Mites
|
|
Meandering
tunnels in leaves |
Leaf miners
|
|
Puckered
leaves curl downwards; plants stunted |
Flea beetles (Phyllotreta
spp.)
|
|
| AFFECTING SEEDS, SEEDLINGS, OR ROOTS: |
|
CONDITION |
CAUSE |
|
Stems
rot near soil line and plant collapses; seeds do not germinate |
Damping off
|
|
Poor
germination, deformed, spindly seedlings with killed growing point |
Seed corn maggots
|
|
| AFFECTING PODS: |
|
CONDITION |
CAUSE |
|
Blossoms
drop |
Excessive heat or
rain, or Western
flower thrips (Frankliniella occidentalis)
|
|
Pitting
and russeting of pods |
May be due to
chilling injury
|
|
Water-soaked
or brown patches on pods; yellow, blotched seeds |
Bacterial blight (Pseudomonas
syringae)
|
|
Holes
chewed in pods |
Caused by several
worms including the following: Cabbage looper, Beet armyworm (Euxoa
auxiliaris) , Corn
earworm (Heliothis zea) , or European corn borer
(Ostrinia nubilalis)
|
