# Presentation: 668952

## 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

## 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 Agriculture**

## 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**Texas Department of Agriculture - Unpublished**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**
**Bogr****á****n – Plant Pathology (& extension)**

## Project Overview

**Fit relative to entire program**
**Project accomplishments – Entomology**
**	****	****November 2000 – March 2003**
**Tangibles**
**Future directions**

## Aphid Population Growth

**	****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**

**Nitrogen**
**ppm N**

**Chamber**
**N = 6**

**Greenhouse**
**N = 10**

## Aphid Population Growth

## Thrips Population Growth

**	****0****	****19.50****	****35.80**
**	****19****	****179.33****	**
**	****38****	****181.67****	****71.80**
**	****75****	****268.00****	****137.10**
**	****375****	****449.00****	****352.10**

**Nitrogen**
**ppm N**

**Chamber**
**N = 6**

**Greenhouse**
**N = 10**

## Insecticide Applications

**	****0****	****0.80****	****0.80****	****0.80****	**
**	****75****	****1.20****	****1.80****	****1.80****	**
**	****375****	****1.20****	****2.80****	****3.00**

**Nitrogen**
**ppm N**

**Conserve**
**N = 5**

**Orthene**
**N = 5**

**Talstar**
**N = 5**

**Control**
**N = 5**

## Thrips Densities

**	****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**

**Nitrogen**
**ppm N**

**Conserve**
**N = 5**

**Orthene**
**N = 5**

**Talstar**
**N = 5**

**Control**
**N = 5**

## Proportion Flower Damage

**	****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**

**Nitrogen**
**ppm N**

**Conserve**
**N = 5**

**Orthene**
**N = 5**

**Talstar**
**N = 5**

**Control**
**N = 5**

## Plant Height

**	****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**

**Nitrogen**
**ppm N**

**Conserve**
**N = 5**

**Orthene**
**N = 5**

**Talstar**
**N = 5**

**Control**
**N = 5**

## Leaves Per Plant

**	****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**

**Nitrogen**
**ppm N**

**Conserve**
**N = 5**

**Orthene**
**N = 5**

**Talstar**
**N = 5**

**Control**
**N = 5**

## Opened Flowers Per Plant

**	****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**

**Nitrogen**
**ppm N**

**Conserve**
**N = 5**

**Orthene**
**N = 5**

**Talstar**
**N = 5**

**Control**
**N = 5**

## 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 Bogr****án, undergraduate interns)**
**Growth in TAES/TCE faculty with ornamentals emphasis (Carlos Bogr****án, 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’ 

_**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.

## Slide 23

## Bottom       Middle        Apical

**Bottom       Middle        Apical**

**Quick Rinse of  Aphid    Exudate**

## Total Plant DM  (g)

**Fertility Level (ppm N)**

## 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**

## N (%)

**Fertility Level (ppm N)**

**0****	****    19****	****         38****	****    75****	****        375**

**Phys. Mat Leaves**

**Young Leaves**

## Fertility Level (ppm N)

**Fertility Level (ppm N****)**

**Aphids No.**

## Summary:

_**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.):

_**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.

##  Experiment Harvest

** **_**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.**

## Slide 39