Temperature is among the key factors impacting the establishment and spread of invasive pests. The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the major pests attacking Solanaceae plants and is known to possess overwintering capacities. However, the cold hardiness of T. absoluta pupae is poorly documented. In this study, we investigated the effect of constant temperature and stepwise cooling on T. absoluta pupae under laboratory conditions. For this purpose, bioassays on pupal development under constant temperature (5°C) for 30, 60 and 90 days, and stepwise changes in temperature (11, 10 and 8°C; in this order every 30 days), were assessed. We found that exposure to 5°C for 30 and 60 days did not affect the post-cooling emergence time of adults compared to the control. Pupae completed their development after 60 days of cold exposure at 5°C, but more adults emerged after 30 than 60 days. Even though alive pupae were observed after 90 days of cold exposure at 5°C, no adults emerged. External colours of pupae depended on the duration of cold periods, and green pupae obtained after 30 and 60 days were found to be positively correlated with the emergence of adults. When pupae were kept at 11°C for 30 days, 47% emerged, and when the temperature was changed to 10, only 12% of pupae emerged for the period 31–60 days. However, the decrease of the temperature to 8°C yielded no emergence for the period 61–90 days. Our study provides useful information to better understand the population dynamics of overwintering T. absoluta, and to underpin the development of monitoring and control strategies for the pest.

The South American tomato moth, Phthorimaea absoluta (Meyrick), is one of the key pests of tomato in India. Since its report in 2014, chemical control has been the main means of tackling this pest, both in the open field and protected cultivation. Despite regular insecticidal sprays, many outbreaks were reported from major tomato-growing regions of South India during 2019–2020. A study was conducted to investigate the effect of insecticide resistance on biology, biochemical enzymes, and gene expression in various P. absoluta field populations viz., Bangalore, Kolar, Madurai, Salem, and Anantapur to commonly used insecticides such as flubendiamide, cyantraniliprole, and indoxacarb. Increased levels of insecticide resistance ratios (RR) were recorded in P. absoluta populations of different locations. A significant increase in cytochrome P450 monooxygenase (CYP/MFO) and esterase levels was noticed in the resistant population compared to susceptible one. Through molecular studies, we identified four new CYP genes viz., CYP248f (flubendiamide), CYP272c, CYP724c (cyantraniliprole), and CYP648i (indoxacarb). The expression levels of these genes significantly increased as the folds of resistance increased from G1 to G20 (generation), indicating involvement of the identified genes in insecticide resistance development in P. absoluta. In addition, the resistant populations showed decreased fecundity, increased larval development period, and adult longevity, resulting in more crop damage. The information generated in the present study thus helps in understanding the development of insecticide resistance by P. absoluta and suggests the farmers and researchers to use insecticides wisely by adopting insecticide resistance management as a strategy under integrated pest management.

Tuta absoluta (Meyrick) has become a serious menace to sustainable production of tomato in Kenya. A survey was conducted between April 2015 and June 2016 to determine its distribution, abundance, infestation, and damage levels on tomato, and associated natural enemies. Trap counts of T. absoluta moths were recorded in all surveyed 29 counties, which indicated its nationwide distribution irrespective of altitude. Tuta absoluta was present in both open fields and greenhouses. The highest moth/trap/day was 115.38 ± 15.90. Highest leaf infestation was 92.22% and the highest number of mines and larvae per leaf were 3.71 ± 0.28 and 2.16 ± 0.45, respectively. Trap captures in terms of moth/trap/day were linearly and positively related to leaf infestations in open fields (R2 = 0.81) and greenhouses (R2 = 0.61). Highest fruits’ infestation and damage were 60.00 and 59.61%, respectively, while the highest number of mines per fruit was 7.50 ± 0.50. Nesidiocoris tenuis (Reuter) and Macrolophus pygmaeus (Rambur) were identified as predators of T. absoluta larvae. Nine species of larval parasitoids were recovered from infested foliage, with a combined parasitism of 7.26 ± 0.65%. Hockeria species was the most dominant (31.25%) and accounted for 12.88 ± 1.47% parasitism. Two species of larval parasitoids, Hockeria and Necremnus were obtained from sentinel plants with an average parasitism of 1.13 ± 0.25. The overall abundance and parasitism rates of recovered natural enemies were low to effectively control the field populations of T. absoluta. These findings form the basis of researching and developing effective and sustainable management strategies for the pest.

Tuta absoluta (Meyrick) is considered as a major pest of tomato worldwide that causes significant losses in the crop production. This study aimed to evaluate integration of two effective and environmentally safe methods (host plant resistant and biological control) for sustainable management of the pest under greenhouse conditions. The experiment was conducted based on the factorial design with ten replicates under greenhouse conditions (22 ± 3°C, 50 ± 10 RH and 14 L:10 D photoperiod). Infestation to T. absoluta was conducted at the first-flowering stage of the plants by introducing a pair of newly emerged adults (one female and one male) per plant. Ten days later, the biological agent, Trichogramma brassicae, was released on the treatments by hanging a card contained 50 parasitized eggs in each replicate. Observation was performed weekly on ratio of infested leaves per plant (%), number of larvae/plant, number of mines/leaf and ratio of infested fruits/plant (%). Results indicated that the susceptible variety alone (Izmir) supported the highest ratio of infested leaves (42.92 ± 1.95%), number of larvae/plant (12.86 ± 0.71), number of mines/leaf (1.29 ± 0.07) and infested fruits/plant (18.8 ± 1.10%), whereas the lowest (6.12 ± 0.42%, 1.85 ± 0.13, 0.18 ± 0.02 and 0.12 ± 0.06%, respectively) were observed in combined resistant variety (Cherry) and parasitoid released treatment. Integration of these methods not only decreases damage caused on tomato leaflets and fruits, but also reduces insecticide applications which are adversely impact human health and environment.

Biotic factors (including insect pests) constrain field-grown tomato production in Senegal. However, little information is available on the identity and life system of key pests. The objectives of this study were to: (i) update key pest records of field-grown tomato in the central vegetable-producing area along the northern coast of Senegal, known as the Niayes area; (ii) map their spatial and temporal incidence and (iii) understand insecticide use by growers to control the pests. A total of 98 tomato fields distributed in three zones along a north–south transect in the Niayes area were monitored over four crop cycles from 2012 to 2014. As expected, the tomato fruitworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) was the most destructive pest with an occurrence of 92% in sampled fields (90/98) and up to 38% damaged fruits in one field at the time of sampling. The proportion of damaged fruits did not differ among zones, but was significantly higher in the early dry season compared to the late dry season. The invasive tomato leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) was detected in 53% of sampled fields (52/98), mainly in the south of the Niayes area in the late dry season. Because of their ability to adapt to unstable environment and insecticides, this insect pest assemblage is a new challenge that farmers have to deal with while decreasing their use of broad-spectrum insecticides.

The predators Macrolophus basicornis (Stal), Engytatus varians (Distant) and Campyloneuropsis infumatus (Carvalho) consume large numbers of tomato pests such as Bemisia tabaci (Gennadius) and Tuta absoluta (Meyrick). However, they are zoophytophagous and feed on plant parts as well. We evaluated the type and effect of injury caused by nymphs and adults of these mirids on tomato seedlings and fruit in the absence of prey. For each mirid species, seedlings were exposed to groups of 20 nymphs or adults for 72 h, and fruits were exposed for 48 h to groups of four nymphs or adults. Type and the number of injury on stems, petioles and leaflets of tomato seedlings and fruits were recorded after removal of insects. Nymphs and adults of these mirids caused necrotic rings on the leaflets, but no injury was observed on stem and petioles. The necrotic rings on leaflets consisted of blemishes, characterized by feeding punctures surrounded by a yellowish, bleached area. The number of necrotic rings did not exceed one per individual mirid and seedlings developed normally. Nymphs also caused feeding punctures on tomato fruit, but in even lower numbers than on leaflets. Two weeks after the start of the experiment the tomato fruit still looked fresh and feeding punctures had disappeared. Adults did not cause any injury to tomato fruit. The results indicate that nymphs and adults of these zoophytophagous mirids cause little injury to tomato seedlings and fruit, even when present in high densities and in the absence of prey, making them interesting candidates for biological control.

An invasive pest, Tuta absoluta (Meyrick) has been observed infesting tomato Solanum lycopersicum L. (Solanales: Solanaceae) in Central Uganda. The affected farmer made the report, and upon visiting the farm, we observed tiny larvae, green to cream in colour with a black head feeding on tomato leaves, fruit, as well as tender stems. Also, we saw several tiny moths resting on screen house linings. Delta traps baited with TUA-Optima® (Russell IPM) were set in and around the affected farm. Dozens of moths were attracted and trapped on the sticky surface of the traps. The team tentatively identified the insect as T. absoluta. Scientists at the International Centre of Insect Physiology and Ecology (icipe) in Nairobi, Kenya identified the insect using morphological features and molecular techniques.