Planning and control of IPM for greenhouse tomato growers : processes used by expert consultants : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Agricultural Systems & Management at Massey University
Given the clean, green image used to promote New Zealand produce, greenhouse tomato growers are under pressure to shift from conventional pest control to more environmentally-friendly methods such as IPM. However, growers often lack the specific knowledge required to tailor IPM strategies to their properties. Greenhouse consultants with expertise in IPM may provide a valuable source of assistance in terms of IPM adoption. However, little is known about how expert greenhouse consultants conduct this task. This study investigated the processes used by expert greenhouse consultants to assist greenhouse tomato growers with the planning and control of IPM strategies. A Multiple case study research method was selected as the most appropriate method for meeting the study objectives. Following the review of the literature, two expert greenhouse consultants were selected, and the data were collected using semi-structured interviews, field observations, and relevant documentation. Qualitative data analysis techniques were used to analyse the data. The two consultants were found to use similar IPM consultancy processes which, for the purpose of this study, have been separated into the physical activities, and planning and control processes. Both consultants perform similar physical activities (telephone calls and visits) to those used by farm management consultants. However, the two consultants studied distinguish between planning and control purpose telephone calls and visits, which the farm management consultants do not. In addition, both consultants use additional communication tools during the control stage. Throughout the consultancy processes, rapport is considered important to enable a trusting relationship to be built between the client and the consultant. The study highlights the presence of three phases during the consultancy processes, which were not mentioned in other farm management consultancy literature. The "screening" phase is used to ensure the development of the client's favourable attitudes toward IPM in the planning process. The "provision of information" phase, which occurs throughout the processes, is critical due to the complex nature of IPM. The "validation" phase is used to confirm the existence of the problems in the control process. During the planning and control processes, the client and the consultant share several roles and responsibilities. As the clients own the problem, they are responsible for making the decisions, implementing the plans, and undertaking monitoring. In order to do this, the clients act as the information providers and receivers for the consultant. The consultant is responsible for understanding the clients' system, providing the information required by the clients and designing the preventative IPM strategies during the planning stage. At this stage, the consultant also provides a monitoring strategy and contingency plans to be used by the clients. During control, the consultant is responsible for validating and diagnosing existence of the problems, providing information about the causal effect of the problems and designing the curative IPM strategies to solve the problems. During the design phase, the consultant uses decision rules to modify his IPM template, according to the need of each client. Factors such as type of crop, greenhouse age, crop age, whitefly population levels, the ability to heat, season, stud height, and persistence period are mentally structured to come up with various Encarsia introduction rates. In contrast, the IPM manual suggests a single Encarsia rate is used for all situations. The Encarsia introduction rates comprise the initial and maintenance rates. Case Study One starts with low rates of Encarsia for 2-4 weeks, followed by increasing the rates. Case Study Two starts with high rates of Encarsia for 6-10 weeks, followed by reducing the rates. Introduction is discontinued when the sustainable level of whitefly parasitism has been achieved. A more detailed IPM manual which allows for the specific circumstances in greenhouse tomato growers' properties is required to assist growers in the adoption of IPM strategies Key words: consultancy, planning, control, IPM, greenhouse tomatoes, Encarsia formosa, multiple case studies.