6. Protected Crops

This section holds documents related to protected crops. It includes many related to the identification and management of pests and diseases.

Act now to control Verticillium wilt of tomatoes (F15/01)
During 2001, a number of tomato crops were severely affected by a wilt disease, generally associated with the fungus Verticillium albo-atrum. Most of the affected crops were produced on rockwool though some were soil-grown. All of the commercial tomato varieties affected were previously thought to be resistant to Verticillium wilt. However, it appears that these varieties are not resistant to this particular strain nor are the commonly used rootstocks. The source of this new strain is not known. HDC Factsheet 15/01 November 2001. Project No. PC 186

Capsid Bugs in Protected Crops (F37/96)
A guide to the recognition of capsids and the damage they cause. Capsid bugs have become a significant problem in protected crops since growers have reduced their use of broad spectrum insecticides in integrated pest management programmes. Project PC123. 1996. F37/96

Disease control in protected lettuce (F07/01)
The objective of this factsheet is to provide guidelines for achieving effective disease control in protected lettuce crops and, most importantly, to minimise the risk of the harvested product exceeding any maximum residue levels (MRLs) set for the approved fungicides. HDC Factsheet 07/01 October 2001.

Disease control in protected lettuce (F23/05)
The objective of this factsheet is to provide the necessary guidelines for achieving effective disease control in protected lettuce crops and, most importantly, to ensure that the harvested product does not exceed any maximum residue levels (MRLs) set for the approved fungicides. HDC F23/05. November 2005

Dithiocarbamate contamination of salad produce and the use of rubber gloves (F12/05)
Tests have shown that handling salad produce with gloves containing natural latex rubber compounds can result in the deposition of reportable levels of dithiocarbamates. This factsheet reports on the results of dithiocarbamate tests from four different glove types and recommends the most appropriate glove types for handling fresh produce. HDC. F12/05. 2005

Early season control of tomato leaf miner (F08/00)
HDC have collaborated in a MAFF LINK (Technologies for Sustainable Farming Systems) project aimed at developing a control strategy for tomato leaf miner that is compatible with the rest of the tomato Integrated Pest Management (IPM) programme, reliable throughout the season and manageable by non-specialist staff. The studies have focused on the use of the parasitic wasp, Diglyphus isaea, and the parasitic nematode, Steinernema feltiae, in classic round tomato cultivars. HDC Factsheet 08/2000. Project No. PC 108

Effect of MACE resistance on aphid control in peppers (HDC News)
The increasing prevalence of MACE resistant aphids on glasshouse pepper crops mean growers may have to modify their control strategy if they are to keep on top of the pest and maintain IPM on the crop. HDC News. March 2004. Pages 18-19

Glasshouse lettuce: reduction of nitrate levels (PC88)
Project report that aimed to collate data currently available on measured nitrate levels in commercial lettuce crops and to evaluate cultural techniques designed to minimise residue levels without influencing crop productivity. Final Report 1993/94. HDC PC88. 1999

Let there be light (HDC News)
Lighting can be a key tool for maximising yield and Quality in protected crops, but is also a very significant cost. To be cost effective lighting needs to be used efficiently, and this depends on understanding both technical and biological aspects of lighting technology. Nigel Paul of Lancaster University reports on current research discussed at a recent international Symposium on Artificial lighting in Horticulture. HDC News. February 2006, pages 28-30

Mealybugs on protected tomato crops (F25/00)
In recent years there has been an apparent increase in mealybug incidence in protected tomato crops in the UK with increasing crop losses reported. A variety of physical, chemical and biological control methods are available to growers, but these are considered to be time consuming, ineffectual or incompatible with integrated pest management techniques. This factsheet summarises the results from a survey of commercial growers to determine the pest status of mealybug on protected tomato crops in the UK and provides recommendations on how to improve existing control methods. HDC Factsheet 25/2000. Project No. PC 161

Meeting the Climate Change Levy Challenge (HDC News)
The climate change levy and rising fuel costs make energy efficiency a key issue for all producers of protected crops. Trials at HRI Efford have shown how savings can be achieved. HDC News. September 2002

Micro-Turbine CHP Units
This document is a guide for growers on the application of micro-turbine CHP units and their application in protected horticulture. HDC, 2002

New results on pepino mosaic of tomato (F11/01)
Pepino mosaic has been found affecting a small number of tomato crops in the UK each year since 1999. Disease symptoms are illustrated in HDC factsheet 12/00, together with guidance on prevention and action to take if the disease is suspected or confirmed. This factsheet summarises new information obtained in the UK and elsewhere since July 2000. HDC Factsheet 11/2001. Project No. PC 181

Optimising the use of abamectin in cucumber and tomato IPM programmes (F18/00)
Abamectin has recently been approved for control of spider mites and leaf miners on protected tomato crops, and spider mites and western flower thrips on protected cucumber crops. This project aims to provide information on its compatibility with natural enemies and give guidelines on optimising its use within(IPM programmes. HDC Factsheet 18/2000. Project No. PC 160

Pepino mosaic virus of tomato - new results on virus persistence and disinfection (F20/03)
This factsheet summarises new information on the efficacy of disinfection treatments against pepino mosaic virus (PepMV) of tomato. Information is provided on persistence of the virus in dried sap at different temperatures, chemical disinfectants suitable for various surfaces within the glasshouse, soaps and sanitisers for food areas and high pressure, hot water washing for plastic trays and the glasshouse structure. HDC Factsheet 20/03 September 2003. Project No. PC 181

Pepino mosaic, a new disease of tomatoes (F12/00)
Pepino mosaic was found affecting tomato crops in both Holland and England in 1999. So far in 2000 there have been a number of outbreaks in both of these countries and also reports from France and the USA. Little is known about this disease although the virus (pepino mosaic virus) occurs naturally in pepino (Solanum muricatum) in the coastal region of Peru. HDC Factsheet 12/2000.

Plant establishment and nutrition (F37/98)
Two factors that influence plant establishment and early yields are nitrogen concentration and transplant age. Project PC 124 aimed to determine the optimum nitrogen concentration of the applied feed during the establishment phase and investigated the effects of plant age on growth and productivity of winter (first) and summer (re-planted) crops. Project PC 111 aimed to determine whether the nitrogen requirement of a young cucumber crop could be reduced once maturity had been reached. HDC Factsheet 37/1998. Project No. PC 111 and PC 124

Polytunnel Code of Practice
The purpose of this Code is to enable growers to demonstrate that they are responding to public concerns regarding social, aestheic and environmental impacts of polythene tunnels. NFU & British Summer Fruits, 2005.

Potato spindle tuber viroid in tomato and new viroid reports (F09/06)
The first confirmed case of Potato spindle tuber viroid (PSTVd) in a UK tomato crop occurred in 2003. Outbreaks have also occurred in recent years in Germany, the Netherlands and New Zealand. PSTVd is an EU listed quarantine pathogen. This factsheet summarises information on the biology and control of this potentially serious notifiable disease. Information is also provided on four other viroid diseases. Project No. PC 212. HDC F09/06. October 2006

Protected tomato: sources, survival and disinfection of Pepino mosaic virus (PepMV) (PC181)
Summary of a project that aimed to provide knowledge of where the Pepino mosaic virus may occur on a nursery after an outbreak; information on survival of the virus on solid surfaces under different environmental conditions; information on survival of the virus in roots in soil; identification of chemical disinfectants fully effective against the virus; and efficacy of high pressure, hot water washing as a method of disinfecting the glasshouse structure and plastic trays. Final report 2003. HDC PC181

Reducing nitrate input on long season tomatoes (F05/95)
Nitrate inputs to long season tomato crops can be safely reduced without loss of yield provided that levels of Nitrate-Nitrogen in the drain do not fall below a critical level. This factsheet details the findings of three studies (1992/1993/1994) in which levels of applied N03-N ranging from 288 ppm to 30 ppm were tested. Environmental benefits were realised alongside financial benefits to the grower. Project PC55 (update) & 55a. 1993. F05/95

Reed beds: treatment of hydroponic run-off (PC67)
Grower summary of a 3 year project that was carried out during 1992-1994 to determine the potential of a reed-bed for cleaning up run-off from hydroponic tomato and pepper crops. The main areas of interest were in the removal of nitrogen and phosphorus from the run-off solution, but levels of all nutrients entering and leaving the bed were monitored. Final Report 1992/94. HDC PC67

Supplementary Lighting
Until recently the number of UK growers using greenhouse supplementary lighting has been relatively small. However, R&D has demonstrated many benefits including improved winter crop quality and lower costs. This documents is a growers guide on equipment selection, installation, operation and maintenance. HDC, 2001

The virus threat (HDC News)
An HDC project has found that Potato spindle tuber viroid doesn’t spread as easily through a tomato crop as scientists had feared, but new viruses remain a threat to the UK industry as growers at the recent Tomato Conference heard. Claire Shaddick reports. HDC News December 2004, page 13

Tomatoes: effective use of pipe-rail boom sprayers (F20/00)
HDC commissioned this project to provide UK tomato growers with practical recommendations for the optimal boom configuration for vertical pipe rail sprayers. The aim was to improve spray retention and distribution within the crop canopy and therefore enable better control of pest and diseases within an ICM programme. Work has now concluded on tomatoes and the recommendations in this factsheet are based on 3 years of detailed trialling. HDC Factsheet 20/2000. Project No. PC 136

Tomatoes: Guidelines for CO2 enrichment. A grower guide
This HDC grower guide provides practical information on CO2 enrichment for greenhouse tomatoes allowing CO2 produced by burning natural gas in boilers or Combined Heat and Power (CHP) units to be used in the most cost effective way. The information presented is based on research on the optimal control of CO2 enrichment for greenhouse tomatoes commissioned by DEFRA and undertaken at Silsoe Research Institute and Horticulture Research International. In addition to the written guidelines, two simple Excel based, stand-alone computer programs have been created for CO2 enrichment of greenhouse tomatoes, where the CO2 is derived from boilers or from CHP units - these are also available here. HDC. 2002

What next after methyl bromide? (HDC News)
For soft fruit growers replacing methyl bromide is a complex issue. Experts set out the pros and cons of the options at an HDC workshop last month. Spence Gunn reports. HDC News April 2005, pages 13-15