Principal insect enemies of the sugar beet in the territories served by the Great western sugar company

Preface

Some damage is done by some pest somewhere every year, causing some loss to individual farmers. Fortunately, we have been free so far from pests damaging very large areas in any one year, and it is confidently hoped that this will always be the case in the territory served by this Company. Nevertheless, it seems wise to have on hand all the information necessary to enable growers to apply proper measures in case of emergency.

There are available a number of bulletins and books published by the Department of Agriculture, Agricultural Colleges and others, dealing with insect pests damaging to sugar beets, but it has been thought of interest and value to beet growers to have this information presented in one book and with due regard to local conditions.

While it is hoped that this Bulletin will be of valuable assistance to the grower of sugar beets by presenting the best known methods of preventing injury and controlling insects which damage this crop, it seems desirable to impress upon him the fact that there is no magical method, no patent medicine, which can be quickly and easily applied.

Good farming, as taught by local experience, practiced consistently every year, will produce bigger yields of beets and minimize the damage done by insects or beet diseases.

For the benefit of those wishing to study the subject more completely, scientific names of insects, other invertebrate animals, and plants discussed, have been given in the Appendix, pages 138 to 146, together with credit for determination. Free use has been made of the literature of beet insects and credit given where it has been quoted.

This Bulletin has been prepared by Mr. A. C. Maxson, Entomologist in charge of the Company's Experimental Farm at Longmont, Colorado.

Credit is due Miss Caroline M. Preston for reproducing the insects for the colored plates.

THE GREAT WESTERN SUGAR COMPANY

Table Of Contents

Page

Introduction 1

Key for Determining Insect Injury to Sugar Beets:

Explanation of Key 4

The Key 5

CHAPTER I Structure 29

Development 29

The Integument 30

Classification 31

Leaf Feeders 31

Biting Insects 31

Sucking Insects 31

Natural Methods 31

Crop Rotation 31

Burning 32

Artificial Methods — Insecticides 32

Control of Biting Insects 32

Control of Sucking Insects — Contact Poisons 33

Repellents 33

Traction Sprayer 33

Care of Sprayers 34

Knapsack Sprayer 36

Hand Sprayer 36

Home-made Sprayer 37

Paris^Green, Caution Regarding the Handling of 37

iii

Table of Contents

CHAPTER II Page

A. Biting Root Feeders 38 a. Western Army Cutworm 41

b. Pale Western Cutworm 45

c. Variegated Cutworm 47

B. Sucking Root Feeders 55

CHAPTER III Leaf Feeders 67

A. Biting Leaf Feeders 67

1 . Leaf-eating Caterpillars 67

a. Sugar Beet Webworm 67

b. True Army Worm 78

c. Alfalfa Looper 81

d. Alfalfa Webworm 84

e. Yellow-bear Caterpillar 86

f. Zebra Caterpillar 87

2. Leaf-eating Beetles 88

a. Larger Sugar Beet Leaf-beetle or Alkali-beetle 89

b. Western Beet Leaf-beetle 90

c. Flea-beetles 91

c-1 . Banded Flea-beetle 92

c-2. Potato Flea-beetle 93

c-3. Three-spotted Flea-beetle 93

d. Spinach Carrion-beetle 94

e. Blister-beetles 96 a. Two-lined Hopper 100

b. Differential Hopper 100

c. Red-legged Locust 100

4. Field Crickets 109

5. Leaf-miners 110

a. Beet or Spinach Leaf-miner 110

iv

Table of Contents

Leaf Feeders — Continued Page

B. Sucking Leaf Feeders Ill

1 . Aphids or Plant-lice Ill

a. Green Peach-aphis 116

b. Black Beet-seed Louse 117 a. False Chinch Bug 119

b. Tarnished Plant-bug 122

3 . Leaf-hoppers 1 23

a. Sugar Beet Leaf-hopper 123

b. Clover Leaf-hopper 126

c. Eutettix strobi Fitch 128

Chapter IV

A. Predacious Insects 130 a. Fiery Hunter 130

b. Bombardier-beetles 130

2. Tiger-beetles 131

3. Lady-beetles or Lady-bugs 132 a. Assassin-bugs 133

b. Ambush-bugs 133

c. Stink-bugs 133

5. Lace-winged Flies 133

6. Wasps 134

a. Digger-wasps 134

a-1. Family Scoliidae 134

a-2. Spider-wasps 134

a-3. Thread-waisted wasps 134

b. Solitary Wasps 135

B. Parasitic Insects 135

1 . Ichneumon-flies 136

3. Chalcis-flies 137

Appendix 138

Index 149

LIST OF TEXT FIGURES

Page

Fig. 1 A good type of traction sprayer for field use. (Original) 33

Fig. 2 Knapsack sprayer. (Original) 36

Fig. 3 Hand sprayer. (Original) 36

Fig. 3-a A Home-made sprayer - 37

Fig. 4 Scales from wing of moth of western army cutworm, highly

magnified. (Original) ' 42

Fig. 5 Adult snapping-beetle, Alaus ocutatus. The larvae of this

beetle feed upon decaying wood. (Original) 52

Fig. 6 A sugar beet infested with sugar beet namatodes. The white bodies of the female nematodes can be seen clinging to the

rootlets. (Original) 60

Fig. 7 A sugar beet affected with curly-top, showing the characteristic dense mass of rootlets. (After C. O. Townsend, Farmers' Bulletin No. 122, U. S. Department of Agriculture) 60

Fig. 8 Small sugar beets infested with the root-knot nematode. The bead-like swellings on the small roots and the enlargements of the main root are caused by the nematodes.

Fig. 9 Sugar beet badly damaged by webworms 69

Fig. 10 Sugar beets badly damaged by webworms 70

Fig. 1 1 Field of sugar beets showing work of the sugar beet webworm.

Fig. 12 Result of spraying— left, unsprayed; right, sprayed 73

Fig. 13 A portion of the compound eye of a tiger-beetle, highly magnified. (Original) 76

Fig. 14 Cross section through burrow of the solitary wasp.

Fig. 15 Hopper dozer. (After Charles R. Jones, Bulletin No. 233,

Colorado Agricultural Experiment Station) 102

Fig. 16 Exposed grass roots, showing grasshopper eggs and larvae of

the ground beetle, Amara obesa. (Original) 106

Fig. 17 Hair worm escaping from a parasitized ground beetle.

Fig. 18 The hair worm shown in Figure 17, after it had escaped from

the beetle. (Original) 108

Fig. 19 Grasshoppers killed by the fungous disease, Empusa grylli.

VI

List of Text Figures

Page

Fig. 20 An exposed colony of plant-lice on a common roadside weed.

Fig. 21 Leaves of white ash curled by a plant-louse. (Original) 112

Fig. 22 Gall of sugar beet root-louse on leaves of narrow-leaf Cottonwood. (Original) 113

Fig. 23 A common wingless aphid; honey tubes at "A". (Original) . . 1 13

Fig. 24 A branch of Euonymus species, showing star-shaped fruit.

Fig. 25 Sugar beet showing characteristic curling of leaves caused by curly-top. (After Harry B. Shaw, Bulletin No. 181, U. S. Bureau of Plant Industry) 124

Fig. 26 Cross section of sugar beet, showing darkening of rings caused by curly-top. (After C. O. Townsend, Bulletin No. 122, U. S. Bureau of Plant Industry) 125

Fig. 27 Entrance to burrow of tiger-beetle larva. There is never any

loose soil at the entrance to these burrows. (Original) . . 131

Fig. 28 Same burrow as shown in Figure 27, with head of larva resting on level with the surface, ready to seize a victim. (Original) ". 131

Fig. 29 Nest of a mud-dauber, taken from rafter of an out-building.

Fig. 30 A cabbage-worm killed by the larvae of a Braconid, the cocoons of which are fastened to the window screen near it. (Original) 136

The impression may be gained that the sugar beet is especially liable to insect injury because of the bringing together of so much on the subject. However, this is not the case. A study of crop insects shows that most crops have an equal number of insect enemies and many have more. It should be emphasized that everything known to good farming practice in beet culture, such as rotation of crops, manuring, clean culture, and timeliness of plowing and irrigating, tends to minimize damage by insects.

By knowing in advance the structural plan of the Bulletin, reference can more readily be made to any desired part. Hence an outline is given on page 3. Furthermore, the use of this Outline in conjunction with the "Key for Determining Insect Injury to Sugar Beets" (pages 5 to 8) may aid in identifying insects. For example, if it is known that damage is being done to the leaves of the beets and that the insects causing it are "Biting" insects, and if it is known that they are not beetles or grasshoppers, then it can, for practical purposes, be concluded that the damage is being caused by either leaf-miners or caterpillars, and by referring to the text cited, a conclusion can in most cases be drawn regarding the particular insect causing the damage. If one of the suspected insects has been caught, the Colored Plates (See pages 11 to 27) will greatly facilitate its identification.

KEY FOR DETERMINING INSECT INJURY TO SUGAR BEETS

In order to facilitate the use of this Bulletin for reference purposes, a short "Key for Determining Insect Injury to Sugar Beets" has been constructed. (See pages 5 to 8.) If the nature of the insect damage is known, reference to this "Key" should enable one to determine the general class of insect doing the damage, if not the particular insect. By looking up the descriptive pages cited in the "Key", and by checking the Colored Plates against the suspected insect, if one has been caught, a reasonably strong case can probably be established.

It took the artist three seasons to complete the drawings from which the Colored Plates were made. Every insect was drawn directly from a live specimen, and the form and colors are true to life.

Some of these colored pictures were enlarged. In nearly all such cases a small black and white outline at the left or right of the colored picture shows the natural size of the specimen. The exceptions are clearly noted on the title pages.

Pictures as well prepared as these carry descriptions much more quickly and accurately than words, especially to persons not trained to think in entomological terms.

The main purpose of all this care in preparing these Colored Plates is to enable the reader to identify, in the easiest and most positive manner possible, any specimens he may have procured.

The title page opposite each plate gives the name of each specimen and indicates the pages of the Bulletin on which it is discussed.

Additional help in locating the pages on which any individual insect is discussed may be had from the Outline of the Bulletin (page 3), the "Key for Determining Insect Injury to Sugar Beets" (pages 5 to 8), the Appendix (pages 138 to 146), and Index (pages 149 to 157).

THE APPENDIX

The Appendix (pages 138 to 146) contains an alphabetical list of the popular names of insects and plants discussed, together with their scientific names, credit for their determination, and illustration and page references. The Appendix is mainly for the benefit of those wishing jx> study the subject more fully than has been done in this Bulletin.

THE INDEX

The Index will be found at the back of the book, on pages 149 to 157.

THREE METHODS FOR LOCATING DESIRED TEXT

1. If you know the name of the insect, use the Index (pages 149 to 157) or the Appendix (pages 138 to 146) to find the pages of the Bulletin on which it is discussed.

2. If you know the nature of the damage, but not the name of the insect doing it, use the "Key for Determining Insect Injury to Sugar Beets" (pages 5 to 8) or the Outline (page 3).

3. If you have one of the suspected insects, but do not know its name, use the Colored Plates (pages 1 1 to 27) .

Use both Methods 2 and 3 when possible, to make identification more positive.

In case of doubt as to the identity of an insect or other specimen, or as to the nature of an injury, competent advice can always be obtained by consulting the authorities of the Agricultural College, the County Agents, or The Great Western Sugar Company's fieldmen.

REFERENCE FIGURES

The small elevated figures found occasionally throughout the text after the mention of some insect, refer to the corresponding marginal figure in the Appendix. The purpose of the reference is to connect the particular species to its scientific name.

The Bibliography (pages 147 and 148) contains a list of publications on related subjects. Some of these have been drawn upon in the compilation of this Bulletin, and credit given in the text.

Key for Determining Insect Injuring Sugar Beets

Index

EXPLANATION OF KEY FOR DETERMINING INSECT INJURY TO SUGAR BEETS

The method of using the Key (pages 5 to 8) is illustrated below by imagining a case of injury and following it through the Key until we come to the point where we get a clue to the insect causing the damage.

Example: In going through the field while the thinners are at work, we notice a beet here and there which is wilted and cut off just below the surface of the ground. Take your Key and begin at "A." This says that the leaves of the plant are wilted while those of the surrounding plants remain normal. This is true of the plants we found, so we read what comes under "1." As our beet is cut off below the surface of the ground "1" fits our case, so we continue to "a" and read: "Plants small. Damage occurring before or shortly after blocking and thinning". As the thinners are at work in our field this again fits our case, so we pass on to the single star (*). Here we read: "Plants cut off at or just below the surface of the ground," etc. This is our case exactly, and at the end we read: "Look for Cutworms." Thus the Key indicates that cutworms are at work on our beets and refers us to pages 38 to 48 of the Bulletin, where this insect is discussed.

Let us suppose that when we read the paragraph under the single star (*) we found that this did not describe our beet. We would then pass on to the double star (**), and if the beet we have has been injured by any of the insects discussed in this Bulletin this paragraph should describe the way it is injured.

If the injury was not indicated by a wilting of the leaves we pass from the capital "A" to capital " B", on page 6, and if this does not fit our case we pass on through the capital letters until we do find the description. When we find it we pass through the other steps which are indicated by figures, small letters, etc., until we come to the place where the insect causing the injury is named.

While this Key may not fit all cases exactly, yet it should enable one to determine quite closely what insect is causing the injury noticed. Then if the discussion of this insect and the nature of its injury are read and the insect, if one is secured, is compared with the pictures in the Colored Plates, there should be little difficulty encountered in identifying the culprit.

In case of doubt competent advice can always be obtained by consulting the authorities of the agricultural colleges, county agents or the sugar company's fieldmen.

KEY FOR DETERMINING INSECT INJURY TO SUGAR BEETS

A. Leaves of plant wilted while those of surrounding plants remain normal.

1. Plants cut off above the surface of the ground, at varying depths

below, or with portions of the root surface eaten away, leaving shallow depressions or deep pits with darkened walls.

a. Plants small. Damage occurring before or shortly after

blocking and thinning.

* Plants cut off at or just below the surface of the ground.

Damage most apt to occur where beets follow alfalfa or grain, timothy or abandoned crops, and on fields adjacent to alfalfa.

Look for Cutworms (pages 38-48).

** Plants cut off an inch or so below the surface of the ground. Tip of root as pulled from the ground dark, almost black. Damage most apt to occur where beets follow alfalfa, sod, pasture or meadow.

Look for : White Grubs (pages 48-52) ; Wireworms (pages 52-54).

b. Beets larger. Damage occurring from time roots attain the

size of one's finger until harvest.

* Plants always cut off above surface of ground or with

deep cavities pecked into the crowns. Damage most apt to occur near standing alfalfa or waste land overgrown with weeds or other tall growth.

Damage caused by Pheasants.

** Plants never cut off above the surface of the ground.

Portions of root surface eaten away, leaving shallow depressions with rough darkened surface. Root often entirely eaten off several inches below the surface of the ground. Damage usually occurring where beets follow sod, pasture or meadow, or on river bottom land.

Look for White Grubs (pages 48-52).

00 Portions of root surface eaten away, leaving small, deep, dark-walled pits. Roots of large beets never entirely eaten off. Damage most apt to occur where beets follow alfalfa, sod, pasture or meadow.

Look for Wireworms (pages 52-54).

2. Plants not cut off. Portions of root surface not eaten away.

Leaves often dull, dark green, as though plants were suffering from lack of moisture; or leaves yellowish green.

a. Only young heart leaves wilted. Wilting usually most appar-

ent at tip of leaves. Later these tips become dry and brown.

Look for Tarnished Plant-bugs (pages 122-123).

b. Entire plant more or less wilted.

* Root either covered with whitish substance or with abnormal development of fine roots or wart-like swellings.

Root more or less covered with a white mould-like substance. Many whitish-yellow lice mixed with this substance. Lice present in nearly every field regardless of previous crop. Damage more apt to be severe in dry years than wet.

Sugar Beet Root-lice (pages 55-59).

00 Root with abnormal development of fine rootlets. Many small pearly-white bodies clinging to these rootlets. (See Figure 9, Plate III, Page 15 and Figure 6, Page 60). In late fall many of these bodies become rich brown in color. Injury most apt to occur on old beet ground.

Sugar Beet Nematode (pages 59-64).

000 Roots with wart-like swellings. Rootlets with small, almost round swellings resembling beads on a string. (See Figure 8, Page 64). Injury most apt to occur on old beet ground.

Root-knot Nematode or Gallworm (pages 64-66).

** Root normal. Not as above.

Damage usually most severe in fields near poor stands of alfalfa overrun by shepherd's-purse, fanweed and other weeds of the mustard family. Fields adjacent to waste land overgrown with these weeds very apt to be damaged, also, as weeds begin to ripen.

Look for False Chinch Bugs (pages 1 19- 121).

B. Leaves dull green, light yellow, or blotched with whitish green or purple.

1. Leaves dull green, as though plants were suffering from lack of moisture. In severe cases leaves become light yellowish green. Plants making poor growth.

Look for : Sugar Beet Root-lice (pages 55-59); Nematodes (pages 59-66).

2. Leaves blotched with whitish green. Not abnormally curled.

Look for : Plant-lice (pages 111-116),

Leaf-hoppers (pages 123-128).

3. Leaves blotched with purple (Figure 1, Plate VIII, Page 25).

Look for Leaf-hoppers (pages 123-128).

C. Leaves with portions of blade or stem eaten away. Sometimes crowns of beets eaten also.

1. Leaves eaten full of small holes (Figure 1, Plate IV, Page 17).

Injury most apt to occur during spring and early summer.

Look for Flea-beetles (pages 91-93).

2. Leaves more or less completely eaten, or portions eaten from mar-

gins (Figure 11, Plate III, Page 15V

a. Leaves often more or less covered with a fine whitish web.

Damage caused by worms about one inch long when fully grown. Worms -very active, throwing themselves from the plant when disturbed. Often hanging from leaf by a single thread of web, especially when young.

* Worm dark green, striped, several dark circular spots on each segment of the body (Figure 6, Plate V, Page 19). Web when present usually on blade of leaf near its base. Heart leaves usually eaten last. Excrement of worms scattered over leaves in form of small dark pellets.

Sugar Beet Webworms (pages 67-78).

** Worm lighter than webworm. A pink or flesh-colored stripe on each side (Figure 1, Plate VI, Page 21). Web often among heart leaves. A long tube leading from web to clods on the surface of the ground. Worm usually concealed at end of this tube when not feeding.

Alfalfa Webworms (pages 84-85).

b. Leaves not webbed.

* Damage occurring during spring and early summer, while beets are still small.

° Damage usually most severe on wet alkali land or near such land.

Look for Alkali-beetles (pages 89-90).

co Damage not associated with alkali land. Usually most severe near alfalfa, ditch banks, fence rows or waste land. Edges of leaves eaten. In severe cases entire plant destroyed.

Look for Spinach Carrion-beetles (pages 94-95).

Introduction ** Damage usually occurring during midsummer or later.

° Damage most severe on wet alkali land or near such land. Tender portion of leaf eaten, only a network of veins remaining, which soon become dry and brown.

Look for Alkali-beetles (pages 89-90).

° Damage usually most severe at borders of fieldjnear wild land, waste land, ditch banks and fence rows where grasshoppers are numerous, or near alflafa or waste land overrun with sweet clover, or near grain fields.

Look for: Grasshoppers (pages 98-109);

Alfalfa Loopers (pages 81- 84);

Western Army Cutworms (pages 41-45).

000 Damage usually slight, only a beet leaf here and there being eaten. Not confined to border, but occurring throughout entire field.

Look for : Yellow-bear Caterpillars (pages 86-87) ;

Zebra Caterpillars (pages 87-88) ; Variegated Cutworms (pages 47-48).

D. Leaves very much curled and distorted. Veins much enlarged, often bearing cone-shaped points (Figure 5, Plate VIII, Page 25). Root small and stunted. Rootlets abnormally developed (Figure 7, Page 60). Crown often covered with a sticky syrup-like substance. Curly-top (pages 124-125).

Look for Sugar Beet Leaf-hoppers (Pages 123-126).

PLATE I Pam>

Page

Fig. 1 Western Army Cutworm, Chorizagrotis auxiliaris Grt 41

2 Western Army Cutworm, pupa 41 , 46

3 Western Army Cutworm, adult moth 41, 42, 88

4 Western Army Cutworm, wing of dark individual 41, 42

5 An Ichneumon-fly parasite of the Western Army Cutworm,

Amblyteles longula Cress. (Enlarged) 43, 136

6 A Braconid parasite of the Western Army Cutworm — Mic-

rogaster species (Enlarged) 43, 136, 137

7 Cocoon of Microgaster species (Enlarged) 44, 136, 137

8 Chalcis-fly parasite of cutworms, Berecyntus bakeri bakeri

Howard (Enlarged) 44, 1 37

9 Pale Western Cutworm, Porosagrotis orthogonia Morr 45

10 Pale Western Cutworm, adult moth 45, 46

1 1 Eggs of Pale Western Cutworm (Enlarged) 42, 45, 46

12 Egg of Pale Western Cutworm (Natural size) 42, 45, 46

1 3 Wireworm 52, 53

14 Last segment of Wireworm (Enlarged) 52, 53

1 5 Wireworm pupa 52, 54

1 7 Adult Wireworm (Enlarged) 52, 54

18 Larva of adult Wireworm shown in Figure 17 52, 53

19 White Grub '. 48, 51

20 A small white grub which feeds upon decayed vegetable

matter 48, 5 1

23 Adult White Grub, Ligyrus gibbosus De G 48, 5 1

24 Pupa of True Army Worm 78, 80

25 Adult True Army Worm 78, 80

Note: In case of enlargement, a natural size black and white outline drawing is shown beside the colored picture. Exceptions to this plan on Plate I are Figures 7 and 14.

PLATE. I fif 24-

II Plate II

Sugar Beet Root-louse, Pemphigus betae Doane Paee

Fig. 1 Newly hatched louse feeding on Cottonwood leaf (See "A") . 55, 58

2 Newly hatched louse (Enlarged) 55, 57

3 Upper side of leaf after gall becomes closed 55, 58

4 Side view of young gall 55, 58

5 Fully developed gall 55, 58

6 Full grown stem-mother (Enlarged) 55, 58

7 Full grown second generation louse (Spring migrant)

(Enlarged) 55, 58

8 Antenna of Figure 7 (Enlarged) 55, 58

9 Wingless form of sugar beet root-louse found on beets dur-

ing summer (Enlarged) 55, 58

10 A lady-beetle which feeds upon sugar beet root-lice (En-

1 1 Antenna of wingless louse (Enlarged) 55, 58

12 Antenna of wingless louse (Enlarged) 55, 58

13 Antenna of true male sugar beet root-louse, Figure 16 (En-

14 A true bug, Authocoris melanocerus, which feeds on lice in

gall (Enlarged) 59, 132

15 Larva of lady-beetle (Figure 10), which also feeds on lice

while on beets (Enlarged) 59, 115, 132

16 True male sugar beet root-louse (Much enlarged. Note

minute representation of actual size at left of colored picture) 55, 57

17 Solitary egg laid by female sugar beet root-louse (Enlarged). 55, 57

18 True female sugar beet root-louse (Much enlarged. Note

minute representation of actual size at left of colored picture) 55,57

Note: Incase of enlargement, a natural size black and white outline drawing is shown beside the colored picture. Exceptions to this plan on Plate II are Figures 2, 8, 11, 12, 13

and 17.

% F/g/S

PLATE III

Page

Fig. 1 Beet leaf showing mines made by Beet Leaf-miner (Fig. 3),

and eggs (Fig. 3-A) 1 10, 1

2 Eggs of Beet Leaf-miner (Enlarged) 1 10, 1

3 Beet Leaf-miner (Enlarged) 1 10, 1

4 Puparium of Beet Leaf-miner (Enlarged) 110, 1

5 Adult Beet Leaf-miner, Pegomyia vicina Lintn. (Enlarged) 1 10, 1

6 Black Beet-seed Louse, Aphis euonymi Fabr. (Enlarged) 1 17, 1

7 Winged form of Black Beet-seed Louse (Enlarged) 117, 1

8 Sugar Beet Nematode, Heterodera schachtii Schmidt (Adult

female, much enlarged. The nematode is almost microscopic in size) 59, 64

9 Young beet showing female nematodes on rootlets (Slightly

enlarged) 59, 61

10 Adult male nematode (Much enlarged) 59, 64

1 1 Zebra Caterpillar, Mamestra picta Harr, feeding on beet leaf . 87, 88

Note: In case of enlargement, a natural size black and white outline drawing is shown beside the colored picture. Exceptions to this plan on Plate III are Figures 2, 8, 9 and 10.

PLAT EEL

PLATE IV Page

Fig. 1 Work of flea-beetles on a beet leaf 89, 91

2 Adult Banded Flea-beetle, Systerxa taeniata Say (Enlarged) 92

3 A flesh-fly parasite of grasshoppers, Sarcophage variacauda

Coq. (Enlarged) 105

4 Maggot of Figure 3 (Enlarged) 1 05

5 Adult Potato Flea-beetle, Epitrix cucumeris Harr. (En-

6 Adult Three-spotted Flea-beetle, Disonycha triangularis

Say (Enlarged) 93

7 An immature female Field Cricket 109, 1 10

8 Grasshopper egg-pod 104

9 Young Two-lined Hopper, Melanoplus bivittatus Say (En-

10 Adult female Two-lined Hopper 100, 104

1 1 Outline drawing of tip of female's abdomen, Two-lined

Hopper, showing ovipositor 1 00, 1 04

12 Adult male Differential Hopper, Melanoplus differentialis

Thos., yellow phase 100

1 3 Adult male Differential Hopper, black phase 1 00

14 Adult Red-legged Locust, Melanoplus femur-rubrum De G. 100

1 5 Outline drawing of last segment of male's abdomen, adult

Red-legged Locust 1 00

16 Hair Worm. A parasite of grasshoppers and other insects

— somewhat enlarged. See also Figures 17 and 18, Pages 107 and 108 107, 108

Note: In case of enlargements, natural size outline drawings are shown beside the colored pictures. Exceptions on Plate IV are Figures 9 and 16.

PLATE JI

CMPRESTON

Fig -76

PLATE V Page

Fig. 1 A half grown grasshopper with Locust Mites attached 105, 106, 107

2 Young mite (Enlarged) 1 06, 1 07

3 Beet leaf with young Sugar Beet Webworm at "A" 67, 75

4 Young Sugar Beet Webworm (Enlarged) 67, 75

5 Portion of beet leaf with Sugar Beet Webworm moth eggs

(Slightly enlarged) 67, 74

6 Full grown Sugar Beet Webworm (Enlarged) 67, 71, 75

7 Sugar Beet Webworm parasite, Cremnops vulgaris 77, 136

8 Sugar Beet Webworm cocoon 67, 75

9 Pupa of Sugar Beet Webworm 67, 75

10 Last segment of Sugar Beet Webworm pupa (Enlarged) . .67, 75

1 1 Adult Sugar Beet Webworm moth, Loxostege sticticalis

12 Puparium of figure 13 (Enlarged) 77

13 A two-winged Tachina-fly parasite (Meteorus loxostegei

Vier.) of the Sugar Beet Webworm (Enlarged) 77

1 4 A Braconid reared from a Sugar Beet Webworm (Enlarged)

77, 136, 137

1 5 Yellow-bear Caterpillar 86, 87

16 Adult Yellow-bear Caterpillar, Diacrisia virginica Fab 86, 87

17 Adult female Locust-mite (Trombedium iocustarum Riley)

and eggs (Enlarged) 106, 107

18 Adult male Locust-mite (Enlarged) 106, 107

Note: In case of enlargement, a natural size black and white outline drawing is shown beside the colored picture. Exceptions on Plate V are Figures 2, 3, 4 and 10.

F7f. /S

12 13

PLATE VI D

Page

Alfalfa Webworm (Enlarged) 83, 84

Pupa of Alfalfa Webworm 84, 85

Last Segment of Alfalfa Webworm pupa (Enlarged) 84, 85

Adult Alfalfa Webworm, Loxostege commixtalis Walker 75, 84, 85

Alfalfa Looper 81 , 83

Cocoon of Alfalfa Looper 81 , 83

Pupa of Alfalfa Looper 81 , 83

Adult Alfalfa Looper, Autographa gramma californica

Speyer 81,83

Itoplectis atrocoxalis Cress, male. An Ichneumon-fly

parasite of the Alfalfa Looper 83, 136

Itoplectis atrocoxalis Cress, female. An Ichneumon-fly

parasite of the Alfalfa Looper 83, 136

An undetermined Tachina-fly parasite of the Alfalfa Webworm (Enlarged) 85

A Robber-fly 78

Syrphus-fly, Syrphus paulxillus Will. (Enlarged) Its larvae

feed on Beet Root-lice 59, 1 16

A two-winged fly (Chloropisca glabra Meign.) whose larvae

are found among Beet Root-lice (Enlarged) 59

A Solitary-wasp (Odynerus annulatus Say), which places

webworms in its nest as food for its young 77, 135

A full grown larva of the Digger-wasp (Fig. 18), surrounded

by skin of a cutworm 45, 134

Cutworm with egg of the Digger-wasp (Fig. 18) attached

near head 45, 1 34

A Digger-wasp {Sphex luctuosa Snw.) carrying a cutworm

into its burrow 44, 1 54

Note: In case of enlargement, a natural size black and white outline drawing is shown beside the colored picture. Exception on Plate VI is Figure 3.

PLATE YL

9 *<*

/ V

Fig/S

Fig. 13

Fy/7

Fif/6

Fig /a

PLATE VII page

Fig. 1 Larva of Alkali-beetle (Enlarged) 89, 90

2 Pupa of Alkali-beetle (Enlarged) 89, 90

3 Alkali-beetle egg (Enlarged) 89, 90

4 Alkali-beetle eggs about natural size 89, 90

5 Adult Alkali-beetle, Monoxia puncticolis Say (Enlarged) . .89, 90

6 Adult Western Beet Leaf-beetle, Monoxia consputa Lee.