**3. Pest management**

Management strategies of greenhouse pests using chemicals were reported to result in several problems, such developments of resistance to chemicals by pests, and environmental and health problems are caused by those chemical pesticides [17]. The possibility of applying biological control programs to problems of greenhouse pests is highly recommended. Even though they will not completely solve the problems, they can reduce pest populations to an acceptable level. Biological control generally requires more time than pesticides to bring a pest population under an acceptable control level [18]. Biological control strategy such as releasing different predators and parasitoids was reported to be environmentally friendly production method of sweet pepper. Applying the biological control program resulted in a high yield of sweet pepper production (35.06%) compared with the control [17]. In this book chapter, various pest control methods are reviewed.

### **3.1 Polyethylene plastic cladding material**

The most commonly used material for greenhouse covering is polyethylene screening plastic, which has an ultraviolet-absorbing characteristic. The material was prepared by adding a specific UV-absorbing compound to raw polyethylene, which makes the plastic material that can stop the transmission of 95% of the UV light (200–380 nm) and transmits 80% of visible light (380–700 nm) [19]. The behaviors of insects can be affected by the modification of UV light. Light at 360–400 nm activates whiteflies (*T. vaporariorum*) to walk and fly [20]. Similarly, the effects of UV-absorbing plastics on thrips, *F. occidentalis*, have also been reported as hostfinding behavior is disrupted [21]. Reduction in reproduction in aphids by deactivation of its flying behavior was reported. For example, reproduction in *M. persicae* is significantly reduced in a greenhouse covered with UV-absorbent plastic [15].

### **3.2 Predators**

### *3.2.1 Phytoseiidae (Acari)*

Many phytoseiid mites are predatory, and several species have been developed as biological control strategies [3]. McMurtry and Croft [22] classify several phytoseiid mites based on their feeding behaviors. Type I species include *Phytoseiulus* spp., mites that are well known as predators of webbing spider mites. Type II mite species

include *Neoseiulus californicus* (McGregor) and *N. fallacis* (Garman), which feed spider mites and others. Type III species, for example, *N. barkeri* (Hughes), *N. cucumeris* (Oudemans), and *Iphiseius degenerans* (Berlese), are generalists that often prefer prey other than spider mites (in whose webbing they may become entangled) and thrips [3].
