SEX in THE GREENHOUSE R 21 SNV Paddy

“SEX in THE GREENHOUSE” R 21 SNV Paddy de Vries Intens Agri Hydro (Pty) Ltd

Nurserymen women ……do it Under Cover …as do the goggos & nunnus

D E R O C S N E

Why is there a problem? Ø With “Modern” farming techniques we attempt to produce plants at their optimal conditions…… within structures that often cannot. Ø Market expects better, faster, stronger, more productive products (at a static price!) Ø Monoculture Ø Ø Less arable land: Urban creep Economic pressure Production “under cover”: Difficult / impossible crop rotation Attempt to create optimal conditions for… = PLANT PRODUCTION / GROWTH ? = STRONG SURVIVABLE PLANTS = PESTS & DISEASES ?

INSECTS & PATHOGENS: Multiplying/breeding in my greenhouses? WHY? • Unless “virgin” structure: Diseases & Insects are endemic • Personnel / visitors are vectors • Other vectors & contaminants • Conditions created for plant production conducive to insect & disease “breeding” (Structure, climate often marginal) • … e. g. : Low light, wet plants, > RH, warm/cold plants • Discussion measurement? Environment? Plants?

Conditions conducive to Insect “breeding”? • Environment – Basic greenhouse conditions • “Host” – Susceptible Plants – Leaf litter/ damp medium

Insects (some) Aphids Whitefly Broadmite TSWV PVY TSWV To. CSV/ TYLCV/ TICV Virus-like symptoms

Understanding the Enemy: Fungus Gnat

Fungus Gnat Larvae spread diseases

Understanding the Enemy: Leaf miner Loss of chlorophyll, lesions, dead tissue: entry point for disease Damp soil / Medium / Leaf litter Re-infection

Understanding the Enemy: WFT TSWV

Understand the enemy: Whitefly Bemesia tabaci BPYV CYSDV CVYV TYLCV To. CSV TICV

Conditions conducive to pathogen “breeding”? • Plant damage = infection • Light – Low light, thin cuticle, “stress”, • RH, Temp – Poor Air movement – Plant wetting period • Overwatering / “Dense” Medium …. . Low AFP • Nutrition e. g. : – Excessive N (& insufficient Ca): Thin cell walls, large soft cells – Excessive NH 4+ (e. g. predisposition to Fusarium) – Weak plants

Understanding the enemy: Pathogens • Too many case studies: • Sexual & asexual stages • Infection/dissemination favour many conditions – High or Low Humidity (dry or wet) – Root Zone: Temp, p. H, Salinity, Anaerobic conditions, Exudates – Low or high Temp (Mostly perfect greenhouse conditions) – Light

QUO VADIS: Prophylaxis Know & understand the source, life cycle and importance / ramifications of insects / diseases in your structure. Know & understand the environmental conditions conducive to infection & spread of insects / pathogens in the structures SWOT: Identify strengths / weak points of the structure, medium, irrigation system etc. Identify pests’ strengths & weak points What can be done, not done, preventative actions

Prophylaxis? HYGIENE – – – Personnel / Visitors Structure, Tables, floors Trays, Lugs etc. Discarded plants, medium Dust control Environment around structure • Free standing water • Weeds • Roads

Prophylaxis? MEDIUM • Medium – Hygiene: Pathogens, Insects, weeds – Composted – Mineral / Toxin content? – AFP – Effect of time – Effect of fertigation on medium

Prophylaxis? CLIMATE – Light: Polyethylene / Shade – Effect of climate control on: • • • Light RH Temp: Ambient, plant, roots Dew point T Leaf wetting Transpiration

Prophylaxis? FERTIGATION – Water quality • Mineral content • Biotic content – Water treatment • Flocculation, Filtration • Disinfection – Cl, H 2 O 2, O 3 – Nutrition – Frequency

Prophylaxis? GENERAL – Insect trapping / prevention – High quality plant material (phyto’ cert’) – Program of disinfection • Tanks, Irrigation lines, filters • Plants, Clothing, hands, shoes, tools, floors, dust prevention … – Preventative spray program: Cocktails, additives Phyto’, Act 36/1947, Act 29/1947 – Regular water analysis: Biotic / Abiotic – Prevention is better than cure – ASK THE POPULATION REGISTER & DEPT HEALTH

Thank You