Fruit Crop Ecology and Management - UVM Apple Orchard

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growing shoots. In contrast, the fungus that causes gray mold on many crops does not manifest itself until flowers or fruit are senescing, sporulating heavily on the dying tissues. Insect infestations are also somewhat predictable. The blueberry maggot fly starts laying eggs on blueberry fruit only as it turns from green to blue, and climbing cutworms prefer young grape buds. The perennial growth of fruit crops creates predictable longterm changes in the composition of habitats for pests and other plant-feeding species. For example, young apple trees have smooth bark, while older trees may have cracked and creviced bark. Therefore, older trees provide excellent overwintering sites for many pests, including codling moth. The fungal pathogen that causes peach leaf curl uses cracks and crevices in older tree bark to overwinter. Knowing the critical period when the crop is susceptible and which pests or pathogens are present can help guide management activities and restrict pesticide applications to times when they are most needed. Fruit Crop Ecology and Management: Chapter 2 Psylla psychology 101 Ecological concept Habitat suitability influences pest abundance. Putting it into practice Manipulate shoot growth to reduce pear psylla numbers. The pear psylla can complete its development only on pear. This important pest is very selective in choosing its host and suitable sites for egg laying. Pear psylla adults deposit most of their eggs on young succulent foliage, and hatching psylla nymphs feed on new shoot growth. Management practices that affect the vigor or period of new shoot growth will affect the severity of pear psylla attack. Reducing overall shoot growth also reduces pear psylla numbers. Carefully manage horticultural practices to avoid excess tree stimulation. Manage fertility to limit new shoot growth but still achieve the desired fruit set and size. Prune trees each year to limit heavy shoot growth. Pull water sprouts from scaffold limbs through the center of trees to remove the tender foliage that psylla prefer. Pull the water sprouts by hand, rather than with loppers, to decrease regrowth. It may also be possible to use chemicals to reduce shoot growth. With black rot of grape, the fungus can infect young grapes for only a limited period of time. About three to five weeks after bloom, the developing berries of many grape cultivars become naturally resistant to infection, so fungicide protection is not needed after that point. Pear psylla young nymphs and honeydew on young pear foliage. A. Schilder E. Burts 43
44 Ecological concept Host and pest development are synchronized. Putting it into practice Factors that predispose plants to pest attack A variety of stresses can affect the plant’s ability to defend itself against attack by pests. Wounding, for instance, may Fruit Crop Ecology and Management: Chapter 2 Windows of opportunity Treat at the appropriate time to avoid infection. To survive, pests and pathogens have to time their development to coincide with availability of susceptible host tissue. They often have a narrow window of opportunity for infection. One good example is mummy berry disease of blueberry. This fungus infects and produces spores on young succulent shoots in early spring. These spores in turn infect the flowers and the developing berries, which become mummified. The fungus overwinters in the mummified fruit on the ground. The mummies require a chilling period followed by a warmup P. Wharton A mummified blueberry with apothecia. in the spring to become active, similar to blueberry plants. Fungal activity coincides with early plant growth, so it is important to protect the young succulent shoots and flowers from infection. predispose plants to infection. Eutypa dieback infections of grapevines usually begin in pruning wounds. Leucostoma canker, a common disease of peach, nectarine and sweet cherry, often develops in narrow crotch angles, which are inherently prone to winter injury and splitting when branches are laden with fruit. Hail- and frost-damaged pear and apple shoots are particularly susceptible to the fire blight bacterium. Harvesting equipment may damage fruit plants, predisposing them to infestation by wood-boring insects. Prior attack by pests or pathogens may also predispose plants to further attack by other pests. Grape berry moth damage can promote infection of grapes by gray mold and sour rot organisms. Nematodes feeding on strawberry roots can allow entry of root-rotting fungi such as Pythium and Rhizoctonia, which cause black root rot. In addition, strawberry plants may be predisposed to infection by freezing or waterlogging of the soil, soil compaction and herbicide damage. Other stresses, such as drought and nutrient deficiencies, can also render a plant more susceptible to pests and diseases.
Page 1 and 2: Michigan State University Extension
Page 4 and 5: Fruit Crop Ecology and Management I
Page 6 and 7: Enterprise goals ◆ High quality f
Page 8 and 9: In Chapter 4, we set aside the imag
Page 10 and 11: ecology of the landscape, including
Page 12 and 13: the most important constraint influ
Page 14 and 15: temperature extremes and in seasona
Page 16 and 17: R. Zoppolo/D. Stefanelli R. Zoppolo
Page 18 and 19: cultural factors — such as crop l
Page 20 and 21: grafting compatibility that will in
Page 22 and 23: set and production. Timing of chemi
Page 24 and 25: 6 CO2 So So r en gy 6 H2O Organic a
Page 26 and 27: Two organisms are better than one.
Page 28 and 29: Plants rely on microbes to recharge
Page 30 and 31: quences. Too much nitrogen results
Page 32 and 33: conditions. Residues of legumes suc
Page 34 and 35: protected with mulch. In a mature p
Page 36 and 37: or yield to a level affecting profi
Page 38 and 39: material because of their distinct
Page 40 and 41: Single and multicycle pathogens Dis
Page 42 and 43: pesticides can affect the nature an
Page 46 and 47: Ecological concept Wounds predispos
Page 48 and 49: Adults and larvae generally are ada
Page 50 and 51: After a certain period, in which sy
Page 52 and 53: How pathogens cause disease Spore l
Page 54 and 55: alance of the community is disrupte
Page 56 and 57: Parasites A parasite lives in, on o
Page 58 and 59: W. Yang Mycorrhizael hyphae (the th
Page 60 and 61: sources of sugar. For example, Tric
Page 62 and 63: Pesticide impacts on the community
Page 64 and 65: Such differences lead to significan
Page 66 and 67: soilborne pathogens. Moisture, temp
Page 68 and 69: A. Schilder The causal agent of lea
Page 70 and 71: y ascospores are typically more num
Page 72 and 73: track of GDD accumulation based on
Page 74 and 75: indicates that leaf wetness can var
Page 76 and 77: accumulations were predicted to inc
Page 78 and 79: alance these positive and negative
Page 80 and 81: In the foreground, a ground cover o
Page 82 and 83: Ecological concept Insects can migr
Page 84 and 85: their growers keep costs as low as
Page 86 and 87: A 1997 Food Marketing Institute stu
Page 88 and 89: Working with local governments and
Page 90 and 91: Direct farm marketing is not easy.
Page 92 and 93: Human resources: You can’t raise
Page 94 and 95:
Like many fruit farmers, the Gregor
Page 96 and 97:
Richard H. Lehnert, Joy N. Landis,
Page 98 and 99:
But the future of the commercial ma
Page 100 and 101:
sustainable, but they are the best
Page 102 and 103:
J Japanese beetle 46, 47, 67, 76 L
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Fruit Crop Ecology and Management - UVM Apple Orchard

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