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Floral and Nursery Crop Research Initiative Researchers Meeting March 25, 2003. Minimizing Inputs for Optimal Floriculture and Nursery Crop Pest Management. Kevin M. Heinz & Fred Davies Departments of Entomology & Horticultural Sciences Texas A&M University, College Station.
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Floral and Nursery Crop Research Initiative Researchers Meeting March 25, 2003 Minimizing Inputs for Optimal Floriculture and Nursery Crop Pest Management Kevin M. Heinz & Fred Davies Departments of Entomology & Horticultural Sciences Texas A&M University, College Station
Project Overview • Fit relative to entire program • Project accomplishments - Entomology • Tangibles • Future directions
PESP Sampling AFE IPM ARS Inputs NRI Thrips BC Project Position
Texas Agriculture • 80% of Texans reside in urban areas • Urban and suburban areas compete for limited resource - WATER • Need for reduced inputs in an arid state
Texas Problems? • The Texas Department of Agriculture issued 1331 stop sale orders to Texas greenhouse and nursery growers (1996 – 2000) • 98.8% were issued for the occurrence of pest insects. Texas Department of Agriculture - Unpublished
Inputs and Pest Management • Reducing inputs will reduce plant quality • Reducing inputs will reduce insect problems • At high inputs, prophylactic applications of insecticides • Reduce inputs, reduce insecticides, retain plant quality
Inputs and Pest Management • Chrysanthemum as model • Nitrogen as first input measure • Study three insects: aphids, thrips, leafminers • Assess population dynamics, pesticide applications, and plant quality at varying input levels
Inputs and Pest Management • Heinz - Entomology • Davies - Horticulture • Bográn – Plant Pathology (& extension)
Project Overview • Fit relative to entire program • Project accomplishments – Entomology November 2000 – March 2003 • Tangibles • Future directions
Aphid Population Growth Nitrogen ppm N Chamber N = 6 Greenhouse N = 10 0 19.83 296.50 19 53.50 472.17 38 209.17 616.50 75 570.00 833.33 375 803.17 868.33
Thrips Population Growth Nitrogen ppm N Chamber N = 6 Greenhouse N = 10 0 19.50 35.80 19 179.33 38 181.67 71.80 75 268.00 137.10 375 449.00 352.10
Insecticide Applications Orthene N = 5 Talstar N = 5 Nitrogen ppm N Conserve N = 5 Control N = 5 0 0.80 0.80 0.80 75 1.20 1.80 1.80 375 1.20 2.80 3.00
Thrips Densities Orthene N = 5 Talstar N = 5 Nitrogen ppm N Conserve N = 5 Control N = 5 0 18.20 8.20 11.40 8.60 75 17.40 20.00 19.60 25.00 375 6.60 24.00 22.60 72.00
Proportion Flower Damage Orthene N = 5 Talstar N = 5 Nitrogen ppm N Conserve N = 5 Control N = 5 0 0.55 0.40 0.64 0.20 75 0.20 0.39 0.21 0.17 375 0.22 0.22 0.13 0.32
Plant Height Orthene N = 5 Talstar N = 5 Nitrogen ppm N Conserve N = 5 Control N = 5 0 16.26 16.26 15.98 15.16 75 21.76 22.92 21.56 20.90 375 20.64 23.36 21.56 22.24
Leaves Per Plant Orthene N = 5 Talstar N = 5 Nitrogen ppm N Conserve N = 5 Control N = 5 0 60.20 57.80 56.40 51.20 75 168.80 166.40 185.80 154.20 375 180.60 175.80 204.40 204.40
Opened Flowers Per Plant Orthene N = 5 Talstar N = 5 Nitrogen ppm N Conserve N = 5 Control N = 5 0 5.00 5.40 5.60 4.40 75 23.40 24.60 23.80 21.40 375 25.80 26.60 25.00 29.40
Project Overview • Fit relative to entire program • Project accomplishments - Entomology • Tangibles • Future directions
Tangibles • Demonstrate capability to produce quality chrysanthemums with reduced inputs. • Preparing students for the industry (Karol Burns, Carlos Bográn, undergraduate interns) • Growth in TAES/TCE faculty with ornamentals emphasis (Carlos Bográn, Scott Ludwig)
Fertility Affects on Chrysanthemum × Aphid Interactions: Influences on Plant Growth, Photosynthesis, Ethylene Evolution and Herbivore Abundance Fred Davies Chuanjiu He Amanda Chau Kevin Heinz
Host Plant/Crop: Greenhouse mum ‘Charm’ Biotic Stress:Aphids Abiotic Stress: Fertility Objectives:Determining fertility and aphid influence on plant growth & development and herbivore (NO PESTICIDE STRESSES ADDED) Treatments: 2 aphid levels x 5 fertility levels = 10 trts.
Quick Rinse of Aphid Exudate Bottom Middle Apical
Total Plant DM (g) Fertility Level (ppm N)
Total Bud DM (g) 0 19 38 75 375 Fertility Level (ppm N)
Leaf DM (g) Fertility Level (ppm N)
Total Leaf Area (cm2) 0 19 38 75 375 Fertility Level (ppm N)
Specific Leaf Area (cm2 g-1) Fertility Level (ppm N)
Ethylene Production Rate (pmol g-1 FW h-1) Buds Young Phys. Mat Old Leaf Leaf Leaf
Pn (mol CO2 m-2 s-1) Young Phys. Mat Old Leaf Leaf Leaf
Young Leaves N (%) Phys. Mat Leaves 0 19 38 75 375 Fertility Level (ppm N)
Aphids No. Fertility Level (ppm N)
Summary: • REDUCED PLANT QUALITY: Aphids depressed plant vegetative and reproductive growth, and altered carbohydrate partitioning at high fertility. • Aphid inoculated (AI) plants at high fertility had increased specific leaf area [(SLA), i.e. thinner leaves] and greater leaf area than aphid-free (NonAI) plants. • Aphids caused greater ethylene production in reproductive buds and young leaves of high fertility plants, but had no effect on ethylene evolution in physiologically mature or older - basal leaves.
Summary (con.): • AI plants had lower leaf N than NonAI treatments. • Aphids reduced photosynthesis in young leaves of high fertility plants, whereas physiologically mature and older leaves were unaffected. • Aphid abundance was greatest at high fertility. • A higher proportion of aphids were observed in physiologically mature and older leaves at low fertility, whereas at high fertility young leaves had 33% more aphids than older, basal leaves.
Application to Stakeholders • The morphology and physiological status of chrysanthemum determines its susceptibility to aphids. • Aphids increase ethylene, decrease net photosynthesis, and decrease carbon allocation to leaves and reproductive structures, particularly at higher fertility. • While growing plants under deficient fertility levels is not a satisfactory strategy for reducing insect pests, reducing fertility and pesticide levels and producing healthier, less stress susceptible plants is a realistic endeavor for best management practices (BMP) and IPM systems.
Future • One More Insect Herbivore - Leafminers. • Increase Resolution of Reduced Inputs. • IPM approach to include biological control. • Demonstrations in Commercial Greenhouses. • Incorporation of Plant Pathogen Management. • Inclusion of Water and Water × Nutrient Stresses.