Comparison of strains of Nesidiocoris tenuis against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under geothermal greenhouses in southern Tunisia

Heated greenhouse cultivation in southern Tunisia constitutes a very important axis of agricultural development. Among the problems that are prejudicial to glasshouse tomato crops heated by geothermal waters, the newly introduced Tuta absoluta insect remains little studied in this agro-ecosystem. Biological means in the context of an integrated fight against this formidable pest to better understand the geothermal sector and contribute to the study of this new problem. The monitoring of a population of a native strain of Nesidiocoris tenuis installed naturally in the geothermal greenhouse and a population of one strain introduced into another greenhouse, showed the performance of the indigenous strain which multiplied rapidly and remained until the end of cultivation with a large population arriving at the total elimination of Tuta absoluta

Effectiveness of pheromone traps against Tuta absoluta

International audienceIn the Tunisian south, the heated greenhouses are an important axis of development of agriculture thanks to the big geothermal potential of this zone. Currently, this sector suffers from several phytosanitary problems. In the last years, a new insect, Tuta absoluta, threaten the cultures of cultivated tomatoes in heated greenhouses. To improve control of T. absoluta, the effectiveness of pheromone traps (associated or not with a source of light) and luminous traps (associated or not with water, with limed buckets for limed covers) were compared. The results show that the traps with pheromones significantly catch more adults of T. absoluta compared to all the other types of traps (average number of trapped adults of T. absoluta = 73.4 (± 142)). The luminous traps associated with water, with limed buckets as with limed covers show, as for them, an intermediate effectiveness. In spite of this slightly less effectiveness, the luminous traps have the advantage of low costs of production as well as the advantage of simultaneously capturing males and females of T. absoluta. ; Peer reviewe

Efficacy of Emamectin benzoate, Spinosad and Tolfenpyrad on Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) infesting a tomato crop under geothermal greenhouses in Southern Tunisia

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is considered one of the most devastating pests of tomato crops in geothermal greenhouses. It leads to crop losses reaching 100% among farmers and major tomato exporters. In this research, three insecticides, Emamectin benzoate, Spinosad and Tolfenpyrad were evaluated for their efficacy in the control of T. absoluta larvae in heated greenhouses. These three treatments resulted in a significant reduction in the number of T. absoluta larvae compared to an untreated control. The Emamectin Benzoate, Spinosad and Tolfenpyrad used were effective in controlling this leafminer with efficacy percentages above 60% against young larvae and above 50% against old larvae

Comparison of the effectiveness of the most used chemicals against Tuta absoluta in Tunisia

Control failures with several chemicals have prompted research into the resistance status of Tuta absoluta and the effectiveness of certain active ingredients against this pest. In this context, a comparison was made of the effectiveness of the most widely used chemicals against T. absoluta in Tunisia. The results show that the L1 larval stage of Tuta absoluta is very sensitive to all of the chemicals tested. Stage L2 is sensitive to Spinosad, indoxacarb and emactin, while Bacillus thuringiensis, martine do not cause 50% mortality. L3 stage mortality fluctuates between 20% and 80% mortality. The L4 stage is more affected by the treatment with Bacillus thuringiensis which can go to 100%. Based on these results, chemical treatments should be directed according to the dominant larval stage in the plants

Comparison of strains of Nesidiocoris tenuis against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under geothermal greenhouses in southern Tunisia

Heated greenhouse cultivation in southern Tunisia constitutes a very important axis of agricultural development. Among the problems that are prejudicial to glasshouse tomato crops heated by geothermal waters, the newly introduced Tuta absoluta insect remains little studied in this agro-ecosystem. Biological means in the context of an integrated fight against this formidable pest to better understand the geothermal sector and contribute to the study of this new problem. The monitoring of a population of a native strain of Nesidiocoris tenuis installed naturally in the geothermal greenhouse and a population of one strain introduced into another greenhouse, showed the performance of the indigenous strain which multiplied rapidly and remained until the end of cultivation with a large population arriving at the total elimination of Tuta absoluta

Efficacy of Emamectin benzoate, Spinosad and Tolfenpyrad on Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) infesting a tomato crop under geothermal greenhouses in Southern Tunisia

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is considered one of the most devastating pests of tomato crops in geothermal greenhouses. It leads to crop losses reaching 100% among farmers and major tomato exporters. In this research, three insecticides, Emamectin benzoate, Spinosad and Tolfenpyrad were evaluated for their efficacy in the control of T. absoluta larvae in heated greenhouses. These three treatments resulted in a significant reduction in the number of T. absoluta larvae compared to an untreated control. The Emamectin Benzoate, Spinosad and Tolfenpyrad used were effective in controlling this leafminer with efficacy percentages above 60% against young larvae and above 50% against old larvae

Effectiveness of pheromone traps against Tuta absoluta

peer reviewedIn the Tunisian south, the heated greenhouses are an important axis of development of agriculture thanks to the big geothermal potential of this zone. Currently, this sector suffers from several phytosanitary problems. In the last years, a new insect, Tuta absoluta, threaten the cultures of cultivated tomatoes in heated greenhouses. To improve control of T. absoluta, the effectiveness of pheromone traps (associated or not with a source of light) and luminous traps (associated or not with water, with limed buckets for limed covers) were compared. The results show that the traps with pheromones significantly catch more adults of T. absoluta compared to all the other types of traps (average number of trapped adults of T. absoluta = 73.4 (± 142)). The luminous traps associated with water, with limed buckets as with limed covers show, as for them, an intermediate effectiveness. In spite of this slightly less effectiveness, the luminous traps have the advantage of low costs of production as well as the advantage of simultaneously capturing males and females of T. absoluta

Comparison of the effectiveness of the most used chemicals against Tuta absoluta in Tunisia

Control failures with several chemicals have prompted research into the resistance status of Tuta absoluta and the effectiveness of certain active ingredients against this pest. In this context, a comparison was made of the effectiveness of the most widely used chemicals against T. absoluta in Tunisia. The results show that the L1 larval stage of Tuta absoluta is very sensitive to all of the chemicals tested. Stage L2 is sensitive to Spinosad, indoxacarb and emactin, while Bacillus thuringiensis, martine do not cause 50% mortality. L3 stage mortality fluctuates between 20% and 80% mortality. The L4 stage is more affected by the treatment with Bacillus thuringiensis which can go to 100%. Based on these results, chemical treatments should be directed according to the dominant larval stage in the plants