ENTM 340 Insect Pests of Trees Turf and Ornamentals�

C. Sadof� Purdue University

 

 

Laboratory 8.� Aphids, Adelgids and gall makers

 

I. Field Tour of Gall makers and Aphids

 

II. Aphids-

 

 

 

 

Draw a Giant bark aphid with enough detail to see antennae and cornicles.

 

 

 

 

 

 

 

Examine the specimen plants with aphids. Find and draw old aphid skins. These are what you often find after aphid populations subside.

 

 

 

 

 

 

Where do aphids feed on plants?

 

 

 

 

How do aphids injure plants?

 

 

 

 

Distinguish between the injury of a Tuliptree aphid, a wooly elm aphid, and a Honeysuckle witches broom aphid.��� (see lecture notes)

 

 

 

 

 

How does this affect the management strategy for each of these pests?��

 

 

II.� Spittle bugs

 

 

Why are they called spittle bugs, and how can they injure plants?

 

 

What is another common name of this family?

 

 

 

III. Adelgids

 

A. Draw an Eastern Spruce Gall and a Cooley's spruce Gall. Be sure to examine the specimen with emerged adults (see also slide in lecture)

 

 

 

 

 

 

B. Complete this table.

����������������������������������������������� Cooley's Spruce gall���������������������������� Eastern Spruce Gall

 

 

Wintering Stage on Spruce�������������������������������������������������������

 

�����������������������������������������������������������������������������������������������

Initiation of gall making in relation

to spruce bud development, and

insect stage

 

Alternate host

 

 

Availability of resistant varieties

 

 

3. Pine bark adelgids.
1. What is the host?
2. Where do they feed?
3. What does it look like?

 

 

 

 

IV. Gall Maker Review:

Eastern Spruce Gall Adelgid

Cooley�s Spruce Gall Adelgid

Gouty vein Gall of Maple

Jumping Oak Gall

Oak vein pocket gall

Baldcypress twig midge

Ash flower gall

Maple bladder gall

Wool sower gall

Hedgehog gall

Horned oak gall

Hackberry nipple gall

Hackberry blister gall

Hackberry petiole gall

Hackberry cone gall

 

1. Which of these galls have the principal host in the common name?

 

 

 

2. Which of these galls are caused by eriophyid mite gall makers?

 

 

 

3. Which of these galls are caused by gall midge flies?�� Draw a midge.

 

 

 

 

4. Which of these galls are caused by cynipid wasps?� Draw a Cynipid wasp.

 

 

 

 

5. Which of these galls is caused by heteroptera bugs?� Draw a psyllid and an adelgid.

 

 

 

6. Which of these galls is the most serious threat to trees?

 

 

 

V. Horned Oak Gall

 

 

 

Draw a picture of this gall on the stem.������� Draw a picture of this gall on the leaf midrib.

 

 

 

 

 

 

 

 

How do stem and leaf galls fit into the biology of this insect?

 

 

 

Is this a serious pest?�����

 

 

 

 

 

VI. Hackberry Blister Gall and Hackberry Nipple Gall.

 

Draw each� and dissect to draw the psyllid inside.�

 

 

 

 

 

 

 

 

 

 

 

 

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