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 Floral and Nursery Crop Research Initiative Researchers Meeting March 25, 2003

Project Overview ]Fit relative to entire program ]Project accomplishments - Entomology ]Tangibles ]Future directions

Project Position AFEIPM PESPSampling NRI Thrips BC ARSInputs

 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 Agriculture

Texas Problems? The Texas Department of Agriculture issued 1331 stop sale orders to Texas greenhouse and nursery growers (1996 – 2000) 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. 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 Texas Department of Agriculture - Unpublished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

Aphid Population Growth Nitrogen ppm N Chamber N = 6 Greenhouse N = 10

Aphid Population Growth

Thrips Population Growth Nitrogen ppm N Chamber N = 6 Greenhouse N = 10

Insecticide Applications Nitrogen ppm N Conserve N = 5 Orthene N = 5 Talstar N = 5 Control N = 5

Thrips Densities Nitrogen ppm N Conserve N = 5 Orthene N = 5 Talstar N = 5 Control N = 5

Proportion Flower Damage Nitrogen ppm N Conserve N = 5 Orthene N = 5 Talstar N = 5 Control N = 5

Plant Height Nitrogen ppm N Conserve N = 5 Orthene N = 5 Talstar N = 5 Control N = 5

Leaves Per Plant Nitrogen ppm N Conserve N = 5 Orthene N = 5 Talstar N = 5 Control N = 5

Opened Flowers Per Plant Nitrogen ppm N Conserve N = 5 Orthene N = 5 Talstar N = 5 Control N = 5

Project Overview

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) on plant growth & development and herbivore (NO PESTICIDE STRESSES ADDED) Treatments: 2  aphid levels x 5 fertility levels = 10 trts.

Bottom Middle Apical Quick Rinse of Aphid Exudate

Total Plant DM (g) Fertility Level (ppm N)

Total Bud DM (g) Fertility Level (ppm N)

Leaf DM (g) Fertility Level (ppm N)

Total Leaf Area (cm 2 ) Fertility Level (ppm N)

Specific Leaf Area (cm 2 g -1 ) Fertility Level (ppm N)

Ethylene Production Rate (pmol g -1 FW h -1 ) Buds Young Phys. Mat Old LeafLeaf Leaf LeafLeaf Leaf

Pn (  mol CO 2 m -2 s -1 ) Young Phys. Mat Old Leaf Leaf Leaf Leaf Leaf Leaf

N (%) Fertility Level (ppm N) Phys. Mat Leaves Young Leaves

Fertility Level (ppm N ) Aphids No.

Summary: REDUCED PLANT QUALITY: Aphids depressed plant vegetative and reproductive growth, and altered carbohydrate partitioning at high fertility.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.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.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. 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.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. 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. 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.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.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.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.

Experiment Harvest

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.