Major Symptoms & Possible Causes

Sometimes the cause of a garden problem is easy to identify. Fan shaped mounds of soil littering a lawn are obviously the work of a pocket gopher; slime trials leading to plants with large, ragged holes in the leaves can only mean slugs or snails.

A bigger challenge is deducing the source of trouble when many explanations are possible. Leaf yellowing and wilting, for example, may be due to insects, nematodes, diseases, or improper watering. If you can’t find clear evidence of a pest, the best course is to assume that growing conditions are at fault, then to focus on improving them. If you’re convinced a pest or disease is the villain, check the rogues’ gallery for a likely candidate but be sure all the evidence fits before placing blame.

Your Disease and Pest Control Experts

For help in solving problems you can’t identify on your own, consult your Cooperative Extension office or a reputable local nursery.

SymptomsPossible CausesNotes
Leaf yellowingSpider mites
Root rot diseases
Viral diseases
Over watering
Nutrient deficiencies
Soil chemistry
Old age
Usually pinpoint yellowing
Especially bark borers
Wilting also occurs
Older leaves affected firstOlder leaves affect first
Leaf mottlingViral diseases
Pesticide damage
Natural on some plants
Genetic variegation
Leaf spotsDiseasesInsects
Spider mites
Air pollution
Pesticide damage
Nutrient deficiencies
Soil chemistry
Leaf malformationsSucking pests
Viral diseases
Peach leaf curl
Lack of water
Nutrient deficiencies
Pesticide damage
On peaches and nectarinesEspecially from certain weed killers
Holes in leavesChewing pests
Leaf dropDiseases
Bark borers
Improper watering
Improper light
Air pollution
Nitrogen deficiency
Soil chemistry
Natural on some plants
Deciduous plants
Cankers(sunken lesions)DiseasesInsects
Root stress
Mechanical wounds
Especially borersFrom lawn mowers, pruner, and other equipment
Branch diebackDiseasesInsectsNematodes
Root stress
Soil chemistry
Especially vascular diseases such as firelight and verticillium wilt
Severe infestation by root or foliar pests or twig girdlers
Root rotDiseases
Over watering
Root stress
Soil chemistry
Usually fungal
Discolored tissue inside roots and stemWilt diseases
Fertilizer damage
Root malformationsNematodes
Girdled roots
Natural on some plants
Crown gall, for example
Formed in container
Nitrogen-fixing nodules on legumes
Poor germinationOld Seeds
Uneven irrigation
Incorrect planting depth
Damping-off disease
Soil crusting
Root maggots, wireworms
WiltingLack of water
Especially borers and root feedersRoot rots and wilt diseases

Bonide Products

Citrus, Fruit, Nut, Orchard Spray Concentrate
Fruit Tree Spray Concentrate
Citrus, Fruit & Nut Orchard Spray
Garden Dust
Dragoon Dust w/ Copper

Bayer Products

NATRIA Multi-Insect Control
NATRIA Insecticidal Soap
3-In-1 Insect, Disease & Mite Control
2-In-1 Insect Control Plus Fertilizer Plant Spikes
NATRIA Disease Control
All-In-One Rose & Flower Care
Disease Control For Roses, Flowers & Shrubs
3-In-1 Tree & Shrub Plant Starter
NATRIA Insect, Disease & Mite Control
2-In-1 Systemic Rose & Flower Care
Dual Action Rose & Flower Insect Killer

Fertilome Products

Triple Action Plus (8 oz)
Liquid Systemic Fungicide (8 oz)
Fire Blight Spray (2 oz)

Pest Control

Bug Chart with Solutions
More Fertilome Products
More Bonide Products