The tomato leaf miner (Tuta absoluta): Conventional pest problem, organic management solutions?

Abstract

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a serious pest of solanaceous plants, especially tomato. Commonly known as the tomato leaf miner or South American tomato pinworm and originating from Central America, it has been a major problem there for tomato production for over 30 years. It appeared in Europe in 2006 in Eastern Spain, progressed rapidly around the Mediterranean basin and then throughout Europe, Africa, and Asia. Other countries are being invaded and it is now considered one of tomato’s most devastating pests worldwide in conventional, low-input and organic systems in both field and protected (greenhouse) situations. Crop damage occurs throughout the tomato growing cycle. Larvae feed on foliage, stems and fruit, and as they burrow deep into plant tissues, become protected from contact pesticides and most predators. They are very difficult to control, even with intensive pesticide applications, and yield losses of up to 100 % have been reported in severe epidemics. Commercial tomato hybrids resistant to T. absoluta would be a major component of control strategies in all production systems. However, despite breeders’ efforts, host plant resistance has not yet been achieved in commercial varieties. In the meantime, control of this devastating pest must rely on integrated control programmes adopting a range of available techniques applicable to both conventional and organic, field and greenhouse production systems but without reliance on resistant varieties. This review considers the challenges of T. absoluta control in tomatoes. It begins with a brief summary of the origin, host range, geographical distribution and biology of the insect and the economic impacts of the damage that it causes. Then, chemical and biological control methods and host plant resistance are considered. Evaluation of current knowledge and understanding of T. absoluta, the efficacy of the existing control measures and identification of deficiencies is key to defining and developing regimes which are effective in organic, low-input and conventional production systems against this devastating pest.