South American Tomato Leafminer Research Articles

Molecular confirmation of the presence of the South American tomato leafminer, Phthorimaea absoluta Meyrick, 1917 (Lepidoptera: Gelechiidae) in Lao PDR

Molecular confirmation of the presence of the tomato leafminer, Phthorimaea (Tuta) absoluta Meyrick, 1917 (Lepidoptera: Gelechiidae), in the Paksong region of the Bolaven Plateau in Champasak province in south-western Lao PDR is reported. The moth, which is native to South America, has invaded many countries in Europe, Africa, and Asia since 2006, and, based on regional records possibly entered Lao PDR between 2014 and 2018. It is a devastating pest of solanaceous crops and threatens tomato production worldwide. Further surveys are required to determine its presence in other regions of Lao PDR and effective management programs must be developed to help farmers minimise losses.

Biology, distribution, and management of invasive South American tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera; Gelechiidae), in Asia.

South American tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), is native to South America, but is a major invasive and quarantine pest species in Europe, Africa, and Asia. It causes extensive damage of up to 100% yield loss in tomatoes (Solanum lycopersicum) in open and greenhouse conditions. Since its first invasion in Spain in 2006, it has spread rapidly into many countries in the Mediterranean and Western Europe and further invaded Africa and Asia. In Asia, it was first recorded in August 2009 in Turkey and spread to most South and East Asian countries. In this study, we reviewed existing work on the biology and distribution of T. absoluta in Asia, as well as the damage it causes. This review will help to develop efficient management tactics as well as establish quarantine and phytosanitary precautions in uninvaded countries.

Evidence-based insecticide resistance in South American tomato leaf miner,Phthorimaea absoluta(Meyrick) under laboratory selection

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.

Evaluation of Integrated Management Practices of South American Tomato Leaf Miner Tuta absoluta in Tomato

Tomato is grown in an area of 36000 ha in Chittoor district of Andhra Pradesh. South American tomato leaf miner, Tuta absoluta has become major pest in tomato growing areas causing 50-60% damage. Even though pest damage starts from seedling stage, damage is not noticed by farmers till fruiting stage due to the pest feeding habit, and spraying chemicals repeatedly at this stage is of no use. Moreover, it causes environmental pollution and pesticide residual effects on consumers. Hence, an on-farm trial on integrated management of the Tuta absoluta was conducted during Rabi, 2020-21. The IPM practices included were installation of pheromone traps @ 25 per hectare; spraying neem oil @ 5 ml/l, twice @20 and 40 DAT and need based chemical sprays. In IPM plots, pest damage was low in crop grown under single row planting i.e., 9% followed by double row planting i.e., 12.6% whereas in farmers practice it was 21.5% and 24.3% in single row planting and double row planting respectively in crop planted during December, 2020. Crop planted during January suffered more than December planted cropi.e., in IPM plots it was 12.5% & 15.5% whereas in farmers practice it was 27.6 and 31.2% in single row planting and double row planting respectively. In December planted crop, Fruit yield of 54.2t/ha and 52.8t/ha was recorded in IPM and farmers practice respectively. In January planted crop it was 51t/ha and 49.5t/ha in IPM and farmers practice respectively. IPM along with planting of crop during December under single row method of planting found to be effective in managing the pest.

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

Simple SummaryTomato is the most important vegetable grown in Myanmar. However, its production is threatened by the invasion of the new insect pest, the South American tomato leaf miner, Tuta absoluta. 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. Tuta absoluta presence was confirmed in all fields and locations surveyed in Myanmar, under two cultivation methods, (i.e., floating-and land cultivation). Higher infestation levels recorded at theKalaw location (land cultivation) seemed to correspond with plants at flowering and early harvesting stages. Moreover, information collected from the survey showed that 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 of the survey.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.

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.

Outbreak of the South American tomato leafminer, Tuta absoluta, in the Chinese mainland: geographic and potential host range expansion.

In 2017 Tuta absoluta was identified as an invasive species in China. Due to its rapid geographic expansion and the severe crop damage it causes, T. absoluta poses a serious threat to China's tomato production industry. To determine its geographic distribution and host range, intensive surveys and routine monitoring were conducted across the Chinese mainland between 2018 and 2019. The population colonization coefficient (PCC; ratio of colonized sites and prefectures) and population occurrence index (POI; ratio of infested host species and PCCs) were calculated. In northwestern China, T. absoluta populations established in Xinjiang exhibited a medium PCC value (~0.03). In southwestern China, populations in Yunnan and its five neighboring provinces exhibited high (~0.50 in Yunnan and Guizhou), or low (<0.02 in Guangxi, Sichuan, Hunan, and Chongqing) PCC values. In the Chinese mainland, infestations of four crop plant species (tomato, eggplant, potato, and Chinese lantern) and two wild plant species (black nightshade and Dutch eggplant) were identified; tomatoes were infested in every colonized province. Chinese lantern and Dutch eggplant are potentially novel hosts. Yunnan, Guizhou, and Xinjiang experienced the most serious damage (POI). In southwestern China, observed damage significantly decreased with increased distance from the first discovery site of T. absoluta to the farthest county of an infested province increased. T. absoluta populations are well-established and could potentially spread to other regions of China. The present study helps to inform the establishment of better pest management guidelines and strategies in China and tomato-producing regions worldwide. © 2021 Society of Chemical Industry.

Functional response and egg distribution among hosts by Pseudapanteles dignus, a larval endoparasitoid of Tuta absoluta

AbstractThe functional response of a biocontrol agent has been classically pointed out as a quantitative evaluation criterion to understand its killing capacity to an arthropod pest. In this paper, we revisited the functional response of the internal larval parasitoid Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae), a candidate for biocontrol of the South American tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), measured as the daily egg oviposition of single parasitoid females at increasing densities of T. absoluta larvae through dissection of hosts. The functional response curve of the number of parasitized hosts was fitted out taking into account the number of eggs laid and their distribution among hosts at each T. absoluta larval density. The data also allowed us to discuss the self‐superparasitism strategy of this parasitoid as an adaptive trait. Pseudapanteles dignus showed a sigmoid shape functional response and a contagious distribution of eggs among hosts, favouring self‐superparasitism and laying a similar number of eggs in each superparasitized host at each T. absoluta density. This research is firstly intended to ascertain about the oviposition behaviour of P. dignus and additionally to provide information on its reproduction to be applied in mass rearing procedures and augmentative releases against T. absoluta.

Spatial distribution pattern of South American tomato leaf miner, Tuta absoluta (meyrick) on open field tomato in Andhra Pradesh

Spatial distribution pattern of South American tomato leaf miner, Tuta absoluta (meyrick) on open field tomato in Andhra Pradesh

Development and validation of an integrated pest management strategy against the invasive South American tomato leaf miner, Tuta absoluta in South India

Tomato is one of the most popular vegetables grown in South Asian countries, including India. Introduction of any invasive species to a new environment has always resulted in serious ecological and economical threats globally. One such widely effected invasive pest in tomato cultivation is Tuta absoluta, which was reported infesting tomato fields in India in 2014 for the first time. In order to reduce the over reliance on chemical pesticides, the effectiveness of an integrated pest management (IPM) package including microbial pesticides (Bacillus thuringiensis var kurstaki, Beauveria bassiana), neem products and a chemical pesticide, chlorantraniliprole had been evaluated. Multi-location trials were conducted for two seasons in 2018 and 2019. The findings revealed that the effect of the IPM package in reducing T. absoluta infestation was quite promising in all the experimental trials. The performance of the IPM package was on par with the Farmers' practice (calendar based application of chemical pesticides) in reducing T. absoluta infestation, without any compromise in the marketable yield. The excessive spraying of chemical pesticides in the Farmers’ practice led to an increase in the protection cost at all the experimental sites, which was nearly two times higher than that of the IPM package. Hence, the IPM package can be considered as effective and economical in managing invasive T. absoluta on tomato in South India.

First report of the South American tomato leafminer, Tuta absoluta (Meyrick), in China

Tuta absoluta (Meyrick) originated in South America and is one of the most serious pests of tomatoes. It is also known to attack other solanaceous crops, including potato, eggplant, pepper, tobacco, and weedy species such as black nightshade. After accidental introduction into Spain in 2006, this pest spread rapidly throughout Afro-Eurasia and has become a major threat to tomato production worldwide. Here, we report the first record of T. absoluta as an invasive pest in China. It was found in tomato fields in Ili Kazakg Autonomous Prefecture, Xinjiang Uygur Autonomous Region (Ili, Xinjiang), China, and its occurrence was confirmed by both morphological and molecular approaches. In Ili, T. absoluta has been found to attack eggplant, potato, and black nightshade. We found the larvae generally mining and feeding on leaves and boring into tomato fruits, with multiple larvae sometimes observed in a single fruit. Its infestation levels differ among the tomato fields and host species. In all of the surveyed tomato fields, T. absoluta infested 100% of plants. In some of the fields, up to 90% of the eggplant and 100% of the potato plants were infested. Since no natural enemies were found under field conditions, suitable management practices are urgently needed to stop the further spread of this destructive pest in China.

Morphological, molecular, and pathogenicity characteristics of the native isolates of Metarhizium anisopliae against the tomato leafminer, Tuta absoluta (Meyrick 1917) (Lepidoptera: Gelechiidae) in Ethiopia

The South American tomato leafminer, Tuta absoluta (Meyrick 1917) (Lepidoptera: Gelechiidae), is a newly introduced and a major threat of tomato production in Ethiopia. Laboratory bioassay was conducted to evaluate locally isolated Metarhizium anisopliae (Metsch.) (Sorokin), against larvae of T. absoluta. Twenty-five Metarhizium isolates were isolated from different soil types, using the great wax moth, Galleria mellonella L. baiting method. From these, 13 isolates were prescreened by biological efficiency index model and tested against 2nd and 3rd larval instars of T. absoluta at the concentration of 107 spores ml−1. Sterile water plus Tween 80 (0.1% v/v) was used as a control. Greenhouse reared larvae of T. absoluta were used as experimental organisms. All tested Metarhizium formulations were pathogenic to T. absoluta in all conducted bioassays. Three isolates, AAUM78, AAUM39, and AAUM76, were the most effective and scored 88, 90, and 95% and 90, 93.3, and 95.7% mortality against 2nd and 3rd larval instars of T. absoluta, respectively. The lowest (48.5 and 50%) mortality rate was recorded by isolate AAUM30 against 2nd and 3rd larval instars, respectively, in 7 days post inoculation. However, all isolates showed significant statistical differences with F (24, 50) = 6.825, p < 0.001 and F (23, 15) = 3.97, p < 0.001 of mortality to 2nd and 3rd larval instars, respectively. Molecular analysis categorized these selected isolates under species of M. anisopliae and grouped into 2 different groups. AAUM78 and AAUM39 were recorded LT50 values of 3.93 and 3.5 days at the lowest (104 spore ml−1) concentration and LC50 values of 1.2 × 103 and 2.9 × 103 spore ml−1, respectively. Although AAUM78 and AAUM39 were virulent to the target pest, further field evaluation is required to determine their potential efficacy for T. absoluta control.

პომიდვრის სამხრეთ ამერიკული მენაღმე ჩრჩილის Tuta absoluta (Meyrick, 1917) ბიოეკოლოგიური თავისებურებების შესწავლა საქართველოში

პომიდვრის სამხრეთ ამერიკული მენაღმე ჩრჩილის Tuta absoluta (Meyrick, 1917) ბიოეკოლოგიური თავისებურებების შესწავლა საქართველოში

Geographical Distribution of South American Tomato Leaf Miner Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) in Nepal

South American tomato leaf miner, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is an invasive insect pest of tomato (Lycopersicon esculentum Miller) both in field and controlled environment conditions. T. absoluta is native to South America, it was detected first time in Nepal from Kathmandu during May, 2016. Survey was conducted at 46 locations of 31 districts in terai and mid hills of Nepal during February to June 2018. T. absoluta was detected from 45 locations of 30 districts surveyed. T. absoluta which was detected from Kathmandu, Lalitpur, Bhaktapur, Kavre and Dhading districts in 2016 has now been spread into 33 districts across the Nepal. Apart from 33 districts T. absoluta might be present in other districts which were not surveyed during the study. Farmers generally manage T. absoluta through indiscriminate use of chemical pesticides. So, extensive research is needed in future to develop integrated pest management technique which is suitable and sustainable for its management in Nepalese context.

Occurrence of South American Tomato Leaf Miner (Tuta absoluta) and Current Management Practices Adopted by Farmers in Lalitpur District, Nepal

A study was carried out to document occurrence of Tuta absoluta and current management practices adopted by farmers in Lalitpur district (Lele VDC) where a total of 70 respondents were interviewed using random sampling method. The study comprises three target groups viz. structured questionnaire survey of farmers growing tomatoes (50); structured questionnaire survey of traders involved in tomato business (10); and lastly farmers’ field survey to determine the extent of Tuta absoluta damage in leaves (10). The results revealed in the field Tuta absoluta is the most devastating insect pest and has done the highest 72% losses in the farmer field which is the heavy loss for the farmers and as a result, production of tomato has decreased in 2016 as compared to 2015. However while all the respondents claimed to have faced pest problem only 20% of the respondents were aware about Tuta absoluta. The survey also showed that 70% of the respondents were using para-pheromone lure (TLM lure) while 10% were using para-pheromone lure + light trap, 60% were using botanicals and bio-pesticides like Neem, Bacillus Thuriengensis in alternative ways and 20% were using chemicals like Chlorantraniliprole 18.5% SC (Alcora), Botanical pesticides (Dadaguard), Emamectin benzoate (EMAR 5% WDC), Cyromazine 10% SC (King hunter), Flubendiamide 39.35% SC (FAME 480 SC) without considering their environmental and health risks. All recommended Tuta absoluta control strategies such as pheromone trapping for monitoring as well as suppression, chemical and biological control were not available or known by growers. Trader’s survey showed on an average of 11.7 percent of fruits damage in market where as in farmers field survey revealed an average of 3 percent loss in net house and 10.3 percent loss in open field.

Integrated Management of South American Tomato Leaf Miner [Tuta Absoluta (Meyrick)]: A Review

Tuta absoluta (Meyrick) is one of the newly introduced insect pest of tomato in Nepal, which was first detected by Entomology Division, Nepal Agricultural Research Council from a commercial tomato grower of Balaju, Kathmandu on 16th May 2016. The pest occurs all-round the year within the temperature range of 20-27° C, and therefore, the environment of mid hills and plains of Nepal is suitable for sustaining the pest except during the winter season. T. absoluta pest mainly attacks Solanaceous crops, especially evident in tomato, however, it is also found in non-solanaceous crops. Larva of the pest is devastating causing damage in fruit, leaves and stem, and reducing tomato production by 80-100% in open field as well as in plastic house, if no control measures are carried out. Chemicals, like Spinosad, Chlorantraniliprole and Novaluron are recommended in Nepal for controlling this pest, but studies have revealed the inefficacy of chemical control measures due to wide host range, faster reproducing ability and development of pesticide resistance. Therefore, Integrated Pest Management (IPM) with mass trapping of the pest using pheromone trap, biological control by predator, parasitoid, entomopathogenic microbes, including cultural practices are imperative for the effective control of this pest.

Monitoring South American Tomato Leaf Miner, Tuta absoluta (Meyrick) and Assessment of Management Practices Adopted in Kavre, Nepal

The study was carried out from April-August, 2017 to monitor the population of Tuta absoluta and to assess the management practices being adopted in Kavre, Nepal. Study consisted of two major parts: monitoring of insect population and farmer’s survey. The population of T. absoluta ranged from 51 to 972 in each Wota -T trap. The highest population of the insect in traps were recorded in Dhulikhel followed by Panauti and Banepa. Majority of tomato growers (78%) reported T. absoluta as the most problematic among other pests, diseases and disorders. The data from E-Plant clinic at Panchkhal revealed the degree of severity of T. absoluta in tomato crop. Tomato growers have adopted cultural, physical, mechanical, para-pheromone lures, quarantine, botanical and chemical methods for the management of this pest. Majority of them relied on chemical pesticide (94%) followed by cultural practices (86%) and Tomato Leaf Miner (TLM) lure (66%) based on cumulative percentage of respondents. Use of TLM lure was found as the best in terms of its effectiveness, safety, and practicability. Thus, Integrated Pest Management strategies are essential to limit the significant loss and reduce dependency on chemical pesticides in future.

Effectiveness of Different Types of Traps For Management of Tuta absoluta in Nepal

Among the various potential vegetables, tomato is one of the high value crops, with growing market demand and higher level of return per hector. South American Tomato leaf miner, Tuta absoluta is one of the main constrains in tomato production in Nepal. Field experiments were conducted from June to October 2017 to determine the attractive action of trap colours against T. absoluta management in Lele VDC, Lalitpur, Nepal. Experiments were setup using different types of traps (Delta trap, Wota-T trap and solar light trap) each with pheromone capsule i.e. TLM lure. Particularly, in this experiment the influence of color (orange, white, yellow and green) in delta trap, height adjustment from ground level - 1 feet, 2 feet, 3 feet and 4 feet) in Wota-T trap and; locally prepared light traps of led bulb, solar light trap with high power of 65 lumens and solar light trap with low power of 25 lumens to capture Tuta moth were tested. For the evaluation of effectiveness of different types of traps, number of Tuta moths captured were recorded. The results demonstrated that T. absoluta moths can distinguish between the colours. White colored delta trap captured maximum mean number of Tuta moth (22) followed by green (16), yellow (13) and orange (10). Similarly, Wota- T trap when placed at different height, trap placed at ground level captured maximum mean number of Tuta moths (15) followed by One ft (12), Two ft(11), Three ft(8) and Four ft(2). Among the different types of light trap solar light trap with high power of 65 lumens captured maximum mean number of Tuta moth’s (5) followed by solar light trap with low power of 25 lumens (3) and locally prepared light trap with led bulb (2). Significant differences between mean moth catches by different colored delta traps, wota-T trap placed at different height and different types of light traps were observed. Based on the study conducted with in a season it were found that trap color, trap height and light trap types are the characteristics that strongly affect the response of T. absoluta moths to pheromone-baited traps. From the study it is clear that, these traps can be used as one of the best sex pheromone based management strategy for the management of T. absoluta moths. Further research is recommended for better understanding of the effect of trap colour on the diversity and abundance of non target insects captured

First Report of Invasive South American Tomato Leaf Miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in Tajikistan

For the first time in Tajikistan, South American tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) was detected in greenhouses and open field environments in Khatlon region and the region of Republican Subordination. Leaf damage, although lower at the beginning of the season, gradually rose to 15–30% in surveyed sites. Fruit damage also gradually increased during the season. Fruit damage was as high as 20% in the locations surveyed, with the exception of Guliston and Ghayrat Jamoats, which had very low fruit damage. Tuta absoluta is becoming established in Tajikistan. Suitable integrated pest management strategies are needed to reduce the incidence of this invasive pest species.

Incidence of South American tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and its natural enemies in Southern Karnataka

Surveys carried out in four districts of southern Karnataka viz., Bengaluru Rural, Chikkaballapura, Kolar and Mysuru to know the incidence level of South American Tomato Leaf Miner Tuta absoluta (Meyrick). These undertaken at monthly intervals from July 2015 to April 2016 revealed that the infestation ranged from a low (5.97% leaf) during November 2015 and (1.59% fruit) during July 2015 to a maximum (24.72% leaf and 13.99% fruit damage) during February 2016. The study also evaluated the effect of mulching in reducing the infestation, besides recording two natural enemies from the surveyed areas in southern Karnataka.