Q. After this last rain and gusty winds some sunflower
leaves are scorched. The sunflowers are 3 feet tall, sown from seeds saved from
last year. The leaf scorching runs between the veins but not on all the
plants. Is this normal after this kind
of weather?
leaves are scorched. The sunflowers are 3 feet tall, sown from seeds saved from
last year. The leaf scorching runs between the veins but not on all the
plants. Is this normal after this kind
of weather?
A. This had nothing to do with the weather. Look at the
bottom of the leaves. Sunflowers are notorious bug traps. If this scorching is
from bug damage, you will find lots of bugs feeding on the bottom side of the
leaves.
bottom of the leaves. Sunflowers are notorious bug traps. If this scorching is
from bug damage, you will find lots of bugs feeding on the bottom side of the
leaves.
 |
| Bottom leaves of sunflowers beginning to scorch showing signs of pest problems on the underside |
Bug damage is noticed on the
lowest leaves first and progresses up the plant. Usually insecticidal soap
sprays applied to the bottom of the leaves kill these critters but will not
repair the damage they created.
lowest leaves first and progresses up the plant. Usually insecticidal soap
sprays applied to the bottom of the leaves kill these critters but will not
repair the damage they created.
If the lower leaves turned
yellow, it could be from not enough nitrogen fertilizer. If they are 3 feet
tall, they have already removed a lot of nutrients from the soil to get that
large. Feed them once a month with fertilizer or they will run out of food, the
lower leaves turning yellow and scorching.
yellow, it could be from not enough nitrogen fertilizer. If they are 3 feet
tall, they have already removed a lot of nutrients from the soil to get that
large. Feed them once a month with fertilizer or they will run out of food, the
lower leaves turning yellow and scorching.
 |
| Checking on the undersides of the leaves we can see aphids beginning to colonize, perhaps placed there by ants moving them into virgin territory |
Another possibility is
irrigation or damage from salts. They go hand-in-hand since water washes salt
from around the roots and pushes it deeper. Little plants only require small
amounts of water. Big plants require more water so make sure they are getting
enough water and it is applied often enough.
irrigation or damage from salts. They go hand-in-hand since water washes salt
from around the roots and pushes it deeper. Little plants only require small
amounts of water. Big plants require more water so make sure they are getting
enough water and it is applied often enough.
Improve the soil at the time of
planting with compost, feed the plants regularly with a fertilizer, water them
enough and check for bugs. Then they will be healthier.
planting with compost, feed the plants regularly with a fertilizer, water them
enough and check for bugs. Then they will be healthier.