Tuta absoluta; A Devastating Pest of Tomato: A Review

Tomato (Solanum lycopersicum L.) is a very important vegetable crop of the world. However, there is a huge loss in tomato production due to pest and disease incidence. Tomato leaf miner is a devastating pest of tomato and other Solanaceous crops in many vegetable crop growing areas around the world and it also attacks non-solanaceous crops. The larva is the most devastating stage of tomato leaf miner. After egg hatching, the larvae feed on tomato fruits, leaves, flower buds, and young shoots and create mines and galleries. Larval feeding may reduce tomato production by 80-100 % in an open field as well as in a plastic house if no control measures are carried out. Chemical control has been found ineffective due to a wide host range and has developed resistance to dozens of pesticides. Hence, Integrated Pest Management (IPM) practices involving mass trapping of the pest using pheromone trap, biological control by a predator, parasitoid, entomopathogenic microbes, including cultural practices should be implemented for the effective control of this pest.

Occurrence of the South American Tomato Leaf Miner, Tuta absoluta (Meyrick) in Southern Shan, Myanmar

The South American tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), one of the most important invasive insect pests affecting tomato production worldwide, was for the first time detected in Myanmar. Preliminary surveys on pest occurrence on tomato crops in Myanmar suggested the presence of T. absoluta in Southern Shan State, but there was no official survey conducted until the end of 2019. Therefore, this study aimed to confirm the presence of T. absoluta in Myanmar. The presence of T. absoluta was specifically observed in the Southern Shan State, which is the largest tomato production area in Myanmar, where tomato is grown under two cultivation methods, floating and land cultivation. The highest T. absoluta infestation was recordedat Kalaw with (82%), followed by Inle Lake (i.e., floating cultivation) (20%) and Pin Ta Ya (10%). The amount of T. absoluta larvae was significantly higher in the lower third of the plants, followed by the middle section and upper section, respectively, in three fields surveyed. Potential and severe economic damage may be expected if management practices are not in place to reduce the presence of this invasive pest. It is of immediate importance that plant protection and quarantine offices of ASEAN member states coordinate their response to T. absoluta and build their capacity to monitor the pest and develop a strategy for when it arrives. In addition, a suitable management strategy is needed to reduce the occurrence of this invasive pest.

LARVACIDAL EFFECT OF SOME PLANT EXTRACTS AGAINST TOMATO LEAF MINER (TUTA ABSOLUTA MEYRICK; LEPIDOPTERA: GELEHIIDAE)

Tuta absoluta Meyrick (Lepidoptera: Gelehiidae) is a significant tomato pest, and chemical pesticides are used extensively for its control. Because of the adverse effects of chemical pesticides, researchers have been paying attention more to biopesticides. In this study, the larvicidal effects of the extracts of Tanacetum vulgare (Asteracea), Aleo vera (L.) and (Liliaceae) Tagetes patula L. (Asteracea) was determined and trials were conducted by using leaf dipping and pot methods. The leaf dipping method was conducted in a climate chamber, whereas the potting experiment was performed in the greenhouse. In all of the experiments, second-stage larvae were used to determine the larvicidal effects. According to the results obtained, the highest larvicidal effect and mortality rate was observed at the highest concentration of T. vulgare extract (86%, effect: 86.55%). The lowest mortality rate and the larvicidal effect was observed at the same concentration of T. patula extract (mortality: 79%, effect: 78.55%). In the pot experiment, the highest yield was seen in the Neem Azal T/S, followed by T. vulgare, A. vera and T. patula extracts. On the first day counts, the lowest insecticidal effect was obtained with the lowest concentration of T. patula extract. The extract of A. vera, T. vulgare and T. patula was effective in experiments carried out in pot and laboratory conditions on T. absoluta. It is suggested that more research be done on using these extracts as a biopesticide to control T. absoluta. Keywords: Tomato leaf miner, plant extracts, larvacidal effect.

Evaluation of Bio-Pesticides against the South American Tomato Leaf Miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) in India

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most economically important pests of tomato worldwide. Despite its global importance, the management of this oligophagous pest has still been a challenging task, due to its high capability to develop resistance against synthetic insecticides. Given the limited studies on the effectiveness of different bio-pesticides in India, the objective of this research was to determine the pathogenicity of different commercial formulations of Beauveria bassiana, Bacillus thuringiensis, and neem (Azadirachtin), against T. absoluta, under laboratory and field conditions. For the Bacillus thuringiensis formulations, Green Larvicide® and Delfin® recorded an LC50 of 4.10 × 10⁹ CFU/mL and 8.06 × 106 spores/mg, respectively, while for the B. bassiana formulations, Green Beauveria® and BB Power® were 4.473 × 107 spores/mL and 1.367 × 107 CFU/g, respectively. Furthermore, the results showed high susceptibility to both the commercial neem formulations with Ecotin®, recording an LC50 of 91.866 ppm, and Econeem Plus® recording 212.676 ppm. The results from the field conditions at different locations of Andhra Pradesh, India, showed significant differences (p < 0.001) for leaf and fruit infestation among the interaction effect of treatments and locations. Bio-pesticides, especially neem and B. thuringiensis formulations, reduced T. absoluta infestation similarly to the chemical treatment, without affecting the yield. Therefore, bio-pesticides can be considered as safe alternatives to synthetic pesticides, for the management of T. absoluta.

Study on the effectiveness of chemical and biological agents to control tomato leaf miner (Tuta absoluta Meyrick, 1917)

In growing four tomato varieties in greenhouses, the effect of a conventional and integrated scheme for control of tomato leaf miner (Tuta absoluta Meyrick, 1917) was studied. Six consecutive treatments were performed at ten-day intervals. The conventional scheme includes the following products: Confidor Energy OD 0.08%, Ampligo 150 ZC 400 ml/ha, Coragen 20 SC 200 ml/ha, Exalt 25 SC 2400 ml/ha, Voliam Targo 063 SC 800 ml/ha and Voliam Targo 063 SC 800 ml/ha. In the integrated scheme the following products for plant protection are used – Confidor Energy OD 0.08%, Sineis 480 SC 250 ml/ha, Sineis 480 SC 250 ml/ha, Voliam Targo 063 SC 800 ml/ha, Neem Azal T/S 0.3% and Neem Azal T/S 0.3%. The effectiveness of the plant protection products against the tomato leaf miner, the degree of pest attack of the different varieties and the tomato productivity were studied in this experiment. It was established that in the conventional and in the integrated treatment scheme, the highest efficiency was shown by the product Voliam Targo 063 SC, applied in a dose of 800 ml/ha on the seventh day after spraying. The percentage of damaged plants was the lowest in the variety Clarosa F1 (4.00%), with the application of the conventional plant protection scheme. The results were similar in the integrated scheme – 6.00%, while in the control the degree of infestation reached 18.00%. The percentage of damaged fruits in both treatment schemes was 6.00%, significantly lower than in the control (24.00%). The highest tomato productivity was observed with the application of the conventional plant protection scheme in Manusa F1 variety.