Chief Sign or Symptom Probable Pest or Disease Described Under
Leaves with silvery streaks, black Gladiolus Thrips Thrips
dots of excrement. (Fig- 57)  
  Onion Thrips  
Leaves yellow, perhaps darker Lack of iron Chlorosis
Leaves mottled green. Mosaic Virus Diseases
Leaves yellowed, streaked, or Yellows, Spotted  
spotted. Wilt  
Leaves deformed
Thick, abnormal shape, blackened. Cyclamen Mite (Fig. Mites
Glassy. Broad Mite  
Abnormal shape, thick or fern- 2,4-D Injury Weedkillers
like, curled, twisted petioles. (Fig. 62)  
Leaves curled and blistered. Peach Leaf Curl Leaf Blister
  Oak Leaf Blister  
Young leaves of snowball tightly Snowball Aphid Aphids
curled. (Fig. 5A)  
Leaves curled around white Woolly Aphids  
Leaves puckered or cupped down- Currant, Melon  
ward with lice in pockets on Aphids  
underside. Goldenglow Aphid  
  (on delphinium)  
Leaf enlarged into a gall. Azalea, Camellia Galls
  Leaf Gall (Fig.  
Spruce needles enlarged at base to Eastern, Cooley Aphids
form gall with stem. Spruce Gall Aphids  
Juniper needles enlarged into gall, Cedar-apple Rust Rusts
orange horns in spring.
Small, conical galls on chrysan- Chrysanthemum Gall Midges
themum. Midge (Fig. 37C)  
Galls on oak leaves. Gall Wasps Wasps
Cockscomb galls on elm. Elm Cockscomb Gall Aphids