How Damaging Are Pests

Despite our best efforts to prevent injury, vegetable crops do sustain damage by insects and other pests. The level of loss varies among crops, locations, and years. Also, some pests are consistently injurious, others rarely so. Crop losses were estimated by Met-calf and Metcalf (1993), using various sources, to average about 12.5% for commercially grown vegetable crops in the United States. Undoubtedly, entomologists could quibble about the validity of any estimate, particularly because losses vary so much from region to region and from year to year, but the loss clearly is significant. The estimated crop losses and the economic value of the insect damage (based on 1988 figures) are:

Loss

Crop

crop (%)

$ (millions)

Asparagus

15

22.8

Beans, snap

12

11.8

Broccoli

17

49.7

Cabbage

17

3.8

Carrots

2

6.9

Cauliflower

17

34.4

Celery

14

32.3

Cucumber

20

26.0

Lettuce

7

73.1

Melons

10

9.7

Onion

18

76.7

Pea

10

7.3

Potato

12

230.2

Sweet corn

14

50.5

Sweet potato

5

8.0

Tomato

7

98.5

Watermelon

15

11.3

These losses do not include the cost of preventing insects from causing even greater injury. The financial cost of managing vegetable pests is difficult to estimate, but the value of insecticides alone is measured in hundreds of millions of dollars.

Not surprisingly, the cost of preventing injury varies considerably among locations and crops, and from year to year. As an example, following are some estimates of insect management costs relative to some other crop production and marketing costs for tomatoes grown in central Florida during the spring and autumn growing seasons (based on 1995-1996; Smith and Taylor, 1996):

Average cost during spring and autumn cropping seasons Spring Autumn

Operating costs

Average cost during spring and autumn cropping seasons Spring Autumn

Operating costs

Transplants

224

560

224

560

Fertilizer and lime

326

815

326

815

Scouting

35

87

35

87

Fumigant

562

1,405

562

1,405

Fungicide

175

437

267

667

Herbicide

37

92

37

92

Insecticide

381

952

488

1,220

Labor

347

867

387

967

Machinery

306

765

360

900

Interest

121

302

696

1,740

Total operating

cost

t 3,187

t 7,967

t 3,530

t 8,825

Fixed costs

Land rent

300

750

300

750

Machinery

212

530

255

637

Management

715

1,787

787

1,967

Overhead

894

2,235

984

2,460

Total fixed cost

t 2,122

t 5,305

t 2,328

t 5,820

Average cost during spring and autumn cropping seasons

Spring Autumn

Average cost during spring and autumn cropping seasons

Spring Autumn

$/acre

$/hectare

$/acre

$/hectare

Total preharvest cost

t 5,309

t 13,272

t 5,858 t

14,645

Harvest and marketing costs

Harvest and haul

980

2,450

962

2,405

Packing

2,590

6,475

2,312

5,780

Containers

1,050

2,625

937

2,342

Marketing

280

700

250

625

Total harvest and

marketing costs

t 4,900

t 12,250

t 4,462 t

11,155

Total costs

(per acre/hectare)

110,209

t 25,522

10,320 t

25,800

The cost of insecticide use in the central Florida tomato production region during 1995-1996 was high, $ 380/acre ($ 950/ha) in the spring production period and $ 488/acre ($ 1220/ha) in the autumn period. This does not include application costs because machinery costs are often spread over several practices; for example, fungicides and insecticides are often applied simultaneously. Similarly, fumigation practices are directed primarily to disease and nema-tode management, though weed and insect suppression also accrues. Crop scouting costs cannot be assigned to any particular pest group and are shown separately.

Note that insect-control costs are appreciably higher in the autumn period. This is because of better survival of pests during the summer inter-crop period than the winter inter-crop period, resulting in greater abundance and greater risk of damage. Also noteworthy is that even in the relatively insecticide-intensive Florida cropping system, insecticide costs represent no more than 13.8% of the operating costs, 8.3% of total preharvest costs, and 4.7% of total tomato production costs.

Farmers tend to focus their cost-cutting efforts on the higher priced elements of the crop-production system, often labor and packing operations. The prevalent attitude among most farmers, as long as insecticides are available, effective and affordable, is that their use will minimize an element of risk at relatively low cost. However, if all the pest-related costs are aggregated, the total cost is greatly enhanced, and the true cost of "crop insurance" can be better appreciated. In the Florida tomato production example cited above, the impact of pest management practices is estimated to cost about 49% of operating costs, 29% of total pre-harvest costs, and 17% of total costs.

The use of insecticide is expensive in many crops other than tomatoes. For the period 1995-1996, insecti cide costs on some other vegetable crops grown in Florida were:

Crop

Region of Florida

$/acre

$/hectare

Beans, snap

South

108

270

Cabbage

North

113

282

Celery

South

352

880

Central

201

502

Corn, Sweet

South

211

527

Central

122

305

Cucumber

South

172

430

Eggplant

Central

457

1,142

Pepper

South

427

1,067

Central

387

1,769

Potato

Central

119

297

North

24

60

Squash

South

67

167

Watermelon

South

131

327

Central

48

120

North

9

23

As is evident from this example, insecticide costs tend to be higher in southern Florida than in central and northern Florida (Smith and Taylor, 1996). This is due to the better survival and greater abundance of insects in the subtropical regions of southern Florida. Such variation in insect abundance, and costs associated with insect suppression, are not restricted to Florida, nor are they due only to weather-related factors. The presence of certain prevailing wind patterns, culture of alternate crop hosts, and the abundance of weeds or plant disease also influence the severity of pest damage.

Sometimes insect problems are so severe or expensive that farmers abandon culture of certain crops in a particular area. Home gardeners similarly avoid culture of certain crops if they regularly encounter difficulty. Both farmers and home gardeners sometimes lack the sophistication, motivation, and economic resources to manage pests with the latest and most effective technology. On the other hand, if the garden plot is enough small and the gardener adequately motivated, extraordinary efforts are sometimes applied. The culture of vegetables under row-cover material or screening is a good example of strong desire to overcome pest pressure, or sometimes a strong desire to avoid insecticide use.

How To Can Tangy Tomatoes

How To Can Tangy Tomatoes

Interested In Canning Juicy Tomatoes? Here's How You Can Prepare Canned Tomatoes At Home. A Comprehensive Guide On Tomato Canning. The process of canning tomatoes at home has been a family tradition with many generations. Making home canned or home tinned tomatoes is something that is remembered by families for years! You must have surely seen your granny canning tomatoes at home in order to prepare for the approaching winters. In winters, one is usually unsure of getting fresh tomatoes.

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