Scouting for insect pests is the backbone of all Integrated Pest Management (IPM) programs. The success of IPM programs relies on the insect pest population estimates that scouting methods provide. Scouting methods can reduce the number of pesticide applications by 40 to 60% (Hollingsworth et al., 2000) and pesticide use by 30% (Cloyd et al., 2005). However, most of the scouting methods are unreliable, labor demanding and tedious. Therefore, this research effort recognized the need of the greenhouse industry for a system that is capable of covering a large greenhouse growing area while collecting samples consistently and time efficiently. Two greenhouse scouting methods were selected based on collection efficiency, labor requirements and mechanization feasibility. These methods were the vacuum approach and the sticky card. To allow automatic sampling of insects both scouting methods were prototyped and mounted on an overhead automatic irrigation system. The two prototypes were named: 1) the mobile insect vacuum, and 2) the mobile sticky card. To compare the collection efficiencies of the prototyped mobile methods and a traditional yellow sticky card, greenhouse tests were carried out. Tests were conducted to investigate the effects of two greenhouse air temperatures (13.5 and 28.5°C) and the use of an assisting air jet on the collection of adult whiteflies (Bemisia tabaci) from poinsettia (Euphorbia pulcherrima) cv. Freedom Red canopies. Results from these tests showed that the air assisted mobile insect vacuum had the highest mean collection efficiency (MCE= 3.0 ± 0.5 %). The method was capable of consistently collecting adult whiteflies from poinsettia plants at 13.5 and 28.5°C.
Improvements in the air assisted mobile insect vacuum prototype collection efficiency were deemed desirable for more reliable insect detection. To aid in the design process of the proposed insect collection system, analytical and numerical models based on turbulent jet theory and computational fluid dynamics were proposed. These models can be used to assist in the engineering design of the optimum assisting air jet and intake hood of a vacuum based insect sampling system. The system should provide the required airflow to efficiently collect adult whitefly (Bemisia tabaci) from greenhouse poinsettia (Euphorbia pulcherrima) plants without damaging the canopy foliage. The models can be used to: 1) estimate greenhouse crop canopy drag coefficient, 2) predict centerline air velocities in the collection system flow field and 3) compute the geometries of the assisting air jet nozzle outlet and intake hood suction inlet. Model inputs such as the jet momentum (per unit of time) (J =28 Kg-m/s2) and the suction flow (V_t=1.3 m/s) were determined experimentally and analytically, respectively. Wind tunnel and laboratory tests were performed to determine the poinsettia crop canopy drag coefficient (C_D=0.1 ± 0.01) and the suction and the air jet centerline profiles. The numerical model can be use to simulate several assisting air jet intake configurations, study the collection flow characteristics and evaluate critical geometries. The model has the potential to save prototyping time and money.