Appearing Within . . .

• Do You Have the Answers?
• Diamondback Diversion
• Assisting Natural Wind Pollination of Field Tomatoes with an Air Blower Enhances Yield
• Ways to Remain Competitive
• Critical Periods for Irrigation of Vegetable Crops
• Diagnosing Foliar Diseases of Vegetables
• Consumer Demands Fuel Growth
• Basics of Bug Identification

Notice:
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Announcements . . .

Mark Your Calendar Now !

Texas Plant Protection Conference
December 4 - 6, 2000, College Station, Texas

Overton Watermelon Field Day
TAMU-AREC, Overton, Texas
July 11, 2000, 9:00 a.m - Noon.
Contact Ron Earhart or Marty Baker at (903) 834-6191 for specific information.

Texas Produce Convention
September 6 - 8, 2000
Padre Island, Texas

Do You Have the Answers?

o You Have The Answers? Questioning your practices? Maybe you should! What business are you in? Who are your best customers? Are you a heavyweight or a big player in a unique niche? If not, what are you doing about it? What are your company’s plans for the next 10 years? Did you attend the 1999 Annual Produce Conference?

Do you consider satisfying customers a good benchmark, or should you delight them instead? Do you have all the answers? Is the Internet a threat to your business? An opportunity? Do the financial troubles of Boston Chicken prove home-meal replacement is dead? Are you doing everything you can to capitalize on the tremendous health message fresh produce can deliver? Ever tasted a lychee? Is organic produce a fad? Should you merchandise it in a special section or integrate it throughout the produce department?

Will contract pricing become more prevalent in the years to come? Is consolidation a trend that will continue indefinitely? Does it signal the death knell for small independents or create a huge opening to exploit? Will food safety still be an issue in 2010? Will you still be in business then? Are these questions too hard? Too easy? Are you overconfident?

What are your plans in September 2000? Are you planning to attend this year’s Annual Produce Conference at Padre Island? Do you have all the answers?

Adapted from an article appearing in The Packer, March 22, 1999.

Diamondback Diversion

This article appeared in "The Grower," June-July 1999.

roviding a heaping helping of collard greens may provide relief from the diamondback moth for cabbage, broccoli, and other cole-crop growers.

Everett R. Mitchell, entomologist, USDA-Agricultural Research Service, Gainesville, Florida, is experimenting with collard greens as a trap-crop planted around the edges of cabbage fields. “Invading diamondback moths stop and deposit their eggs on the collards rather than on adjacent cabbage plants,” he said. “Diamondback populations continue to recycle in collards as long as plants remain green, and continue to grow.”

Tests for two years show minimal cabbage damage from the moths’ larvae. The quantity and quality of cabbage produced equaled that from conventionally sprayed fields. “Cabbage fields surrounded by collards required 75 to 100 percent fewer sprays to control diamondback moths than fields treated conventionally with pesticides,” Mitchell said. “That’s a huge savings for farmers.”

Assisting Natural Wind Pollination of Field Tomatoes with an Air Blower Enhances Yield

This is the abstract of an article by H. Y. Hanna which appeared in "HortScience" 34(5):846-847. 1999.

tudies were conducted in 1994, 1995, and 1997 to determine the effect of assisting natural wind pollination, using an air blower, on yield and fruit characteristics of three tomato (Lycopersicon esculentum Mill.) cultivars. Tomato plants and flowers in the air-blower-assisted treatment were vigorously vibrated at midday every other day on sunny days for 4 weeks. Plants and flowers in the control treatment were exposed to ambient wind only.

Early yield was significantly greater in the treated plants at 2 years; marketable and total yields for all tested cultivars were significantly greater in all years; and yields of culls were significantly lower at 2 years. Fruit weight and diameter and number of seeds per fruit were increased in all years.

Ways to Remain Competitive

This article by Ray Klocke appeared in "The Grower", December 1999.

1. Develop strategic alliances or partnerships.
2. Reduce costs, improve services, improve quality, and improve information flow.
3. Co-brand.
4. Pack under a private label for some of the larger chains such as Safeway and Kroger.
5. Develop a unique product that might be done in smaller runs.
6. Develop export markets.
7. Globalize. For example, one grower-packer-shipper can offer grapes year-round to his customers because he’s sourcing them from around the world.
8. Choose varieties based on taste, and promote them. Taste is the next wave that will drive the market in the produce world.
9. Category management.
10. Investigate the latest developments in fields such as proprietary supply technology, on-line sales, and food safety.

Critical Periods for Irrigation of Vegetable Crops

• Asparagus
  Critical Period: Adequate time needed for spear growth, most critical is fern growth
• Broccoli
  Critical Period: During transplant, flower-bud production
• Cabbage
  Critical Period: During transplant, head development
• Carrot
  Critical Period: During root enlargement
• Cauliflower
  Critical Period: During transplant, curd development
• Cucumber
  Critical Period: During pollination and fruit enlargement
• Eggplant
  Critical Period: During transplant, flower, and fruit development
• Lettuce
  Critical Period: Throughout growth
• Lima Bean
  Critical Period: At blossom and pod enlargement
• Muskmelon
  Critical Period: During pollination and fruit enlargement
• Onion
  Critical Period: At planting, and during bulb enlargement
• Pea
  Critical Period: During pod development
• Pepper
  Critical Period: During fruit development
• Potato
  Critical Period: During tuber development
• Rhubarb
  Critical Period: During petiole formation for harvest
• Snap Bean
  Critical Period: During blossom and pod enlargement
• Spinach
  Critical Period: Throughout growth
• Sweet Corn
  Critical Period: During silking and tasseling, and ear development
• Sweet Potato
  Critical Period: When slips are set in the field
• Tomato
  Critical Period: During transplant, early flowering, fruit set, and enlargement
• Turnip
  Critical Period: During root enlargement
• Watermelon
  Critical Period: During pollination, fruit enlargement

This chart by Bill Lamont appeared in The Vegetable Gazette, Volume 3, Number 7, June 1999.

Diagnosing Foliar Diseases of Vegetables

This article by Tom Isakeit appeared in "Valley Vegetable Notes," July-August 1998.

ften, a grower will refer to photographs in books and bulletins for guidance in determining the cause of abnormalities on leaves. However, such materials depict more common symptoms of infectious diseases, and usually the variation in symptom appearance caused by the pathogen is not depicted, nor are many common and uncommon non-infectious causes of similar symptoms. Thus, such material does not depict many commonly encountered symptoms. They should, however, be considered a useful starting point for disease diagnosis.

Although it would be preferable to know the cause of a symptom, if the symptom isn’t getting worse over time (i.e., more of the leaf affected or appearance on other foliage), for practical management purposes, it is sufficient to rule out an infectious cause.

In this article, I will present some general points for deciding whether a symptom is caused by an infectious agent or something else. In making generalizations, I will use watermelons as examples, although these generalizations will also apply to most other vegetable crops.

Generally, leaf-spots caused by fungi tend to be circular (reflecting the pattern of fungal growth) and the affected tissue tends to be dead. Such tissue is either black or brown in color. Furthermore, the discolored tissue is not collapsed in relation to surrounding tissue. This is in contrast to physical or chemical causes of leaf injury, which tend to cause affected areas to become dried up and shrunken.

Sometimes, leaf-spots caused by fungi have very distinctive symptoms, and a photograph is sufficient for making a diagnosis. An example is Cercospora leaf-spot of watermelon. In contrast, photographs of leaf-spots caused by Alternaria or by the gummy stem-blight fungus are just not distinctive enough for diagnostic purposes. Additionally, photographs of advanced symptoms of downy mildew, gummy stem blight, and anthracnose that depict extensive leaf blight are not useful either.

To determine if these particular diseases are present, I recommend that growers remove suspicious leaves and place them in a “moist chamber” at room temperature for 12 to 24 hours. The moist chamber is a small, sealed container (or even a sealed plastic bag) in which a wet paper towel is present to generate a humid atmosphere. Under these conditions, spots will expand, or at least, pathogenic fungi will produce spores on them. The presence of spores can be determined with a good hand lens or a “pocket” microscope. Of course, the identification of these spores does require previous training, but for the purposes of a watermelon grower, that training need not be extensive. I have done such training by simply having infected plant tissue on hand and taking five minutes to show the grower what to look for with a hand lens. The results of a moist-chamber incubation are usually conclusive for diagnosing a fungus disease or ruling it out.

Additional diagnostic clues can be determined by the pattern of symptom appearance in the field. Uniformity suggests a non-infectious cause; for example, leaf-spots that occur over most of a field can be caused by foliar fertilizer burn. Infectious diseases tend to have a clustered distribution in a field. The timing of symptom appearance can also offer a clue. The sudden appearance of similar symptoms suggest a non-infectious cause. If the advanced symptom of an infectious disease is found in a portion of a field, earlier symptoms can also be found. For example, if downy mildew is the cause of a blighted leaf (i.e., dead), leaves with yellow spots - an early symptom - will be found on leaves in close proximity. Finally, the pattern of symptom appearance should be compared to recent weather patterns. A leaf blight occurring when day temperatures are in the 90s with no rain occurring is not caused by downy mildew or gummy stem blight. In fact, leaf-miner insects can be the cause of such blight in different areas of Texas, and they can easily be diagnosed by the presence of serpentine, hollowed-out trails on non-blighted leaves.

Diseases caused by bacteria and viruses will also tend to occur in clusters in the field, and result in a range of symptom stages on plants in that area. So, if the distribution of symptomatic plants is clustered and fungi are ruled out with a moist chamber, these other infectious agents need to be checked out. Unfortunately, this is not always a “do-it-yourself” proposition for growers. There are some diagnostic kits for specific bacterial and viral diseases that are “grower-friendly.” For example, STA Laboratories has an excellent bacterial fruit-blotch testing kit, while Agdia has numerous kits for bacterial and viral diseases on various crops. Another option is to bring samples to a plant-disease diagnostic clinic.

One other consideration is that wilting and yellowing symptoms on the leaves may be caused by infectious agents working on the roots. Be ready to dig up and examine the whole plant.

The grower should strive to quickly identify the presence of foliage-infecting fungi if they occur on the crop. Under the right weather conditions (i.e., moist conditions), these fungi can cause significant yield losses, but if they are diagnosed quickly enough, they can be readily controlled with fungicides.

Consumer Demands Fuel Growth

This article by Jim Offner, Staff Writer, appeared in "The Packer," June 7, 1999.

or many in the produce business, packaging is often as crucial to a customer as the product it contains. As a result, an increasing number of distributors and retailers are getting into the value-added market.

“We get more and more requests for different value-added products,” said Glenn Beckham, produce manger for Allen Fresh Produce Inc., which supplies products in five states. A number of suppliers are beginning to place a heavy emphasis on value-added, making customer convenience central to their company’s ability to compete.

“We’re doing whatever they have difficulty doing at store level,” says Ed Delashmit, president of Sherman Produce Co. Inc., of St. Louis, Missouri. “We’re assembling fruit baskets they don’t have the labor to handle. We’re cutting, trimming, and packaging corn and other items they cannot be doing at store level. If they get short of labor, those kinds of value-added items produced at store level go out the window because they don’t have enough people just to get the stuff on the shelves.”

The right package is a sales tool, said Mike Roberts, produce manager with wholesaler Supervalu Inc. “I think the convenience is the major portion, but I think the visualization of seeing the mature product where it’s already been peeled helps,” he said.

Value-added and fresh-cut products also come with a practical advantage for people concerned with their bottom line.

Basics of Bug Identification

This article by Rick Foster appeared in "American Vegetable Grower," March 1991.

roper identification is the first and most essential step in making appropriate pest-management decisions. Trying to manage insects without identifying them properly would be like asking a doctor to treat an illness without describing your symptoms. If you don’t identify the pest correctly, you may apply an insecticide that is not necessary, apply the wrong insecticide, or apply it at the wrong time. One way to increase your skill in identifying insect pests is to collect as much reference material as possible. Most extension entomologists have numerous publications that will assist you. Many are available free of charge or for a nominal fee. There are also a number of good reference books that have excellent pictures of many insects.

Most insects have one of two distinctly different types of life cycles. The first is called incomplete metamorphosis. With this type of life cycle, the immature insect, called a nymph, looks very much like the adult, except that it is smaller and lacks wings. Insects with incomplete metamorphosis usually feed in much the same manner and on the same food in the immature and the adult stages. Some examples of pest insects that have this type of life cycle include the true bugs, leafhoppers, and aphids.

The other type of life cycle is complete metamorphosis. These insects have an immature stage, called a larva, that looks nothing at all like the adult. The larval stage often feeds in a completely different manner than the adult. There is also a pupal stage which occurs between the larval and adult stages. It is during this stage that the remarkable transition from caterpillar-to-butterfly or maggot-to-fly takes place.

Some examples of insects with this type of life cycle include caterpillars, maggots, and beetles. An important point is that once these insects become adults, they do not grow any larger.

Common Vegetable Pests

• Mites.
  Mites are not insects. Therefore, the best way to identify them is by counting their legs. They have eight, while insects have six. However, mites are very tiny; counting their legs requires the use of a hand lens. Mites have sucking mouth-parts and generally feed on the underside of leaves. Leaves that have had considerable mite feeding will appear off-color, and may show symptoms of wilting. There may also be some very fine silken webbing associated with the mites on the underside of the leaves. Mites tend to be more of a problem during hot, dry weather, so if these conditions occur, be prepared to look for mites. To do this, shake a leaf over a sheet of white paper. If the dust spots walk, you probably have mites.

• Aphids.
  Aphids are soft-bodied insects that occur in colonies on the underside of leaves. They also have sucking mouth-parts with which they remove plant juices from the leaves of most vegetable crops. Leaves that have been fed upon by aphids may become curled. Aphids are rather small insects, usually reaching on a length of 1/16-inch. They may have wings, but most will be wingless. Aphids are somewhat unique insects in that they can reproduce without mating, and give birth to live young. Scout for aphids by looking on the underside of leaves.

• True Bugs.
  Although many people call all insects ‘bugs’ there is only one group of insects that are truly bugs. Most bugs can be recognized by the presence of a triangle on the back directly behind the head. Several different types of bugs damage vegetables, including the tarnished plant bug, some species of stink bugs, chinch bugs, and squash bugs. Bugs range in size from quite small, like the 1/6-inch-long chinch bug, to fairly large, like the 5/8-inch-long squash bug. Bugs tend to be fairly mobile, so scouting for them may require a sweep net, depending on the specific insect and the crop. Some bugs are predators of a number of pest insects.

• Leafhoppers.
  There are a number of sizes, shapes, and colors of leafhoppers. Adult leafhoppers are relatively small, rarely exceeding 1/4-inch in length. Some leafhoppers that are important pests of vegetables include beet leafhopper, potato leafhopper, and aster leafhopper. Adult leafhoppers are very mobile, and often must be sampled with a sweep net or some sort of sticky trap. The nymphs cannot fly, and therefore are much easier to find, usually on the underside of leaves.

• Thrips.
  Thrips are slender, very tiny insects that feed with rasping or scraping mouth-parts. The wings of adults are fringed with long hairs, but these may be difficult to see. Some species are capable of transmitting serious diseases of vegetables. Thrips also feed on small grains and weeds, and may move to vegetables in large numbers when these hosts dry down in summer. They tend to be more of a problem during hot, dry weather. Thrips tend to hide in secluded locations on the plant. On some crops, such as onions and cabbage, plants may have to be taken apart to assess populations. Some thrips that are important on vegetables are onion thrips, western flower thrips, and tobacco thrips.

• Beetles.
  Beetles can be readily distinguished by the hard covering that is formed by one of their pairs of wings. They vary greatly in size, shape, and color. The larvae may be grub-like or almost caterpillar-like. Both adults and larvae feed with chewing mouth-parts. The larvae of some species, such as bean leaf beetles, root-worms, cucumber beetles, and wire-worms, feed on underground portions of plants. Others, such as Colorado potato beetles and Mexican bean beetles, feed on plant foliage in much the same manner as the adults. Many species of beetles are pests of vegetables. Fortunately, most can be easily identified with the aid of the type of publications mentioned previously. Depending on the crop and species of beetle, sampling can be accomplished by direct observation, scouting for damage, and using a sweep net or beat cloth or sticky traps.

• Maggots.
  Maggots are the larval stage of flies. They are usually white, legless, soft-bodied insects that feed in moist locations. Most of the maggots of importance on vegetables feed on the roots or other underground plant parts. The most important maggot pests of vegetables are the cabbage maggot, onion maggot, and seed-corn maggot. The adult stages of these pests are flies, slightly larger than houseflies. Damage is usually more severe during cool, wet weather, and in fields with lots of decaying organic matter. These insects cannot be scouted for because once they can be found, it is too late to do anything. Preventive control must be practiced.

• Caterpillars.
  Probably the largest group of pests on vegetables are caterpillars, which are the larval stage of butterflies and moths. They may vary in size from the diamondback moth larvae (3/8-inch long) to the tomato and tobacco horn-worms (4 inches long). Correctly identifying which species of caterpillar is difficult. Again, make good use of the reference materials you have available. The first step in identifying a caterpillar is to note which crop it is feeding on. This will frequently reduce the number of possibilities to a half dozen or fewer. The size may not be very helpful, since all species start off as very small larvae. However, determining the maximum size may help. Look for distinguishing characteristics such as color, spots, stripes, and the number of prolegs. Prolegs are fleshy appendages on the abdomen that look like legs. Often the number of prolegs can help identify the insect. For example, most species of loopers have two pair of abdominal prolegs. The best ways to sample for most species of caterpillar is by direct observation on the plant, scouting for damage, or by using a sweep net or beat cloth. However, some insects, such as corn earworms on sweet corn, cannot be controlled after they are found. The moths must be trapped with pheromone traps to predict when the eggs will be laid so that protective control measures can be taken before the eggs hatch.

There are more than three-quarter of a million species of insects in the world. Correctly identifying which species are feeding on your crops can be a challenge. However, proper management usually depends on how well you identify the pests you are trying to control.