Pest Of Potato Research Articles

Insecticidal and oviposition deterrent effects of pure and combined essential oils of Salvia subg. Perovskia species against Phthorimaea operculella

Volatile organic compounds especially terpenoid derivatives possess bioactivities including insecticidal effects, and they sometimes act synergistically when mixed. The potato tuber moth (PTM), Phthorimaea operculella Zeller, is one of the most serious pests of potatoes in Iran. Since the potato is an important source of human food, safe and non-chemical control of its pest is indispensable. This study evaluated the fumigant toxicity of pure and two mixtures of essential oils (EOs) of three Salvia subg. Perovskia species against P. operculella. GC–MS phytochemical profiling of species showed 1,8-cineole (12.55%) and linalyl acetate (11.48%), as dominant in S. yangii-EO, geranyl acetate (55.64%), and 1,8-cineole (10.50%) as major constituents in S. abrotanoides-EO, and δ-3-carene (29.29%) and 1,8-cineol (18.08%), as major compounds of S. artemisioides-EO. The EOs, especially combined types were toxic against the pest and showed ovicidal and repellent efficacies. Adults showed considerable sensitivity to the 25:75 mixture ratio of S. yangii and S. abrotanoides EOs (LC50 = 5.82 µL/L air) in comparison to eggs (LC50 = 10.10 µL/L air). The combined EOs also reduced the ovipositional rate. In addition, pure S. abrotanoides EOs showed great fumigant toxicities (11.09 µL/L air) effects against one-old-day eggs. The combination of EOs including 1,8 cineol and geranyl acetate as corresponding compounds, may affect survival, energy resource transfer during oogenesis, and oviposition, which are likely mechanisms involved with essential oil toxicity. As a result, Salvia essential oils can be used for the development of eco-friendly, safe, and effective botanical pesticides in integrated PTM management strategies.

Effects of parasitism by Pyemotes zhonghuajia on reproduction of potato tuber moth

Pyemotes zhonghuajia is an ectoparasitoid natural enemy of a wide range of pests such as Lepidoptera, Coleoptera and Hymenoptera. Phthorimaea operculella (Zeller) (PTM) is a worldwide potato pest with serious damage of potato production. Our study showed that one P. zhonghuajia female could kill 1st to 4th instar larvae of PTM, and the lethal time of one P. zhonghuajia female on first to fourth PTM instar larvae were 5.48, 11.33, 23.47 and 2076 min, respectively. The parasitism of 1, 3, 5, 10, and 20 P. zhonghuajia mites could significantly affect the mortality rate of PTM 4th instar larvae and pupae. The parasitism durations (30 and 60 mins) of one P. zhonghuajia female on one PTM fourth instar larva could influence the life history of PTM parental generation but did not influence the life table of PTM offspring generation. Releasing 60, 80, and 100 mites or opisthosoma with mites could reduce the occurrence and consumption of PTM on potatoes the weight loss of the potato tuber. The number of insect dung piles in one potato tuber was significantly decreased by releasing 60, 80, and 100 P. zhonghuajia mites, and releasing 100 mites resulted in the lowest number of insect dung piles. Our results indicate that P. zhonghuajia can significantly affect the population growth of PTM. Future studies should explore the lethal mechanism of P. zhonghuajia and its performance in practical application in the warehouse and field condition.

First detection of the potato cyst nematode (Globodera rostochiensis) in a major potato production region of China.

The potato cyst nematodes (PCN) Globodera rostochiensis and Globodera pallida are the very important quarantine nematode pests of potato [Stone 1973]. Both species cause serious potato tuber yield losses. These species are subjected to strict quarantine regulations in many countries (EPPO 2017). G. rostochiensis was detected in Sichuan and Yunnan province, China in 2022 (Jiang et al. 2022). A survey for cyst nematodes in potato fields was conducted in Guizhou Province from 2018 to 2020. A total of 200 samples, including roots and soil, were collected from 40 potato fields in Hezhang (N27 06.145, E104 39.153) and Weining (N26 50.541, E104 09.885) counties in Guizhou Province, China. The Cobb decanting and sieving method was used to isolate cysts and J2s from the soil samples (Southey 1986). The potato roots were stained with acid fusion to observe cyst development. Morphological and molecular analyses indicated that 27 (13.5%) of the samples contained G. rostochiensis. The cyst density ranged between 1-85 cysts per 100 cm3 of soil and a mean density was 15 cysts per 100 cm3 soil. The smoothly rounded cysts were in brown and golden color, and the terminal cone was absent and circumfenestrate. The key morphometrics of cysts (n=20) were 695 ± 26 (685-757) μm in length excluding neck and 690 ± 30 (668 to769) μm in width; the number of cuticular ridges between anus and vulval fenestra was 16.3 ±2.1 (14 to 18); fenestral length was 15.1 ± 2.1 μm (13.18 to 19.27); distance from anus to the edge of fenestra was 61.12 ± 8.9 (49.22 to76.27) μm; and Granek's ratio was 4.54 ± 0.8 (3.97-5.26). The key morphometrics of J2 (n = 20): 468.0 ± 20.1 (427 to - 521) μm in body length, 20.58 ± 0.7 (20.2 to 21.8) μm in stylet length, 43.9 ± 5.6 (40.3 to 53.9) μm in tail length, and 23.1 ± 1.8 (21.77 to 25.32) μm in hyaline region length. The cyst and J2 morphologies were consistent with those of G. rostochiensis (Subbotin et al. 2010, EPPO 2017). Genomic DNA was isolated from cysts (n=20). DNA extraction was performed in a volume of 20 μl containing 3 μl 10× PCR buffer, 3 μl Proteinase K (600 μg μl-1), 14 μl distilled water and a single cyst was added and ground in an ice bath as described by Ou et al. (2008). The internal transcribed spacer (ITS) regions were amplified using the universal primers: rDNA1 (5'-TTGATTACGTCCCTGCCCTTT-3') and rDNA2 (5'-TTTCACTCGCCGTTACTAAGG-3') (Fleming 1998 ), and the 28S rDNA-D2/D3 regions were amplified using the primers: D2A (5´-ACAAGTACCGTGAGGGAAAGTTG-3´) and D3B (5´-TCGGAAGGAACCAGCTACTA-3´) (Subbotin et al. 2006). After the brackets at the beginning and end of the sequences were closed-up, the ITS rDNA sequences (GenBank Accession No. MZ042367 and MZ042368) showed 99.66% - 99.92% identity to G. rostochiensis sequences available in GenBank (FJ212166.1, GQ294513, FJ212164.1 and KJ409617.1). Sequences from the 28S region (GenBank Accession No. MZ057597 and MZ057598) were 99.23% - 99.74% similar to those of G. rostochiensis isolate from Slovakia (KJ409625.1), Italy (KJ409631.1) and United Kingdom (KJ409633.1). We used species specific primers ITS5（5'-GGAAGTAAAAGTCGTAACAAGG-3'）and PITSr3 (5'AGCGCAGACATGCCGCAA-3') to amplify the product (Bulman & Marshall 1997; EPPO 2017). A single 434bp fragment was obtained from Hezhang and Weining populations. A host test for the Hezhang and Weining populations were performed by inoculating 1,000 eggs per plant of varieties Qingshu 9, Huize 2 and Hezuo 88 grown in the pots containing 800 cm3 of sterilized soil (soil: sand ratio was 3:1), and four replications were tested in greenhouse under 16 h light, 22°C in the day and 8 h dark in the night. At 90 days post inoculation, 32.6 ± 7, 31.2 ± 8, and 29.5 ± 8 females and cysts were extracted from the infected roots and soils of the varieties Qingshu 9, Huize 2 and Hezuo 88, respectively. No females and cysts were observed on the control plants. The trial indicated that potato cultivars Qingshu 9, Huize 2 and Hezuo 88 are hosts for the Hezhang and Weining populations of Globodera rostochiensis. To the best of our knowledge, this is the first detection of potato cyst nematode Globodera rostochiensis in Guizhou Province, China.

Elevating herbivore-induced JA-Ile enhances potato resistance to the polyphagous beet armyworm but not to the oligophagous potato tuber moth.

The oligophagous potato tuber moth (PTM), Phthorimaea operculella, and the polyphagous beet armyworm (BAW), Spodoptera exigua, are two destructive pests of potato, and infestations can lead to serious reduction in potato yield. However, potato plant responses to the two herbivories are only poorly understood. Endogenous jasmonoyl-isoleucine (JA-Ile) is a signal responsible for the induction of plant anti-herbivore defenses. Elevation of JA-Ile by blocking its catabolism is considered to be an effective and sustainable approach to enhance plant resistance to insect pests. However, it is not clear whether this approach can enhance potato resistance to PTM and BAW. We demonstrated that the transcriptional changes induced by simulated PTM and BAW feeding overlap to a large extent, and that 81.5% of the PTM- and 90.5% of the BAW-responsive genes were commonly regulated. We also generated potato transgenic lines, irStCYP94B3s, in which the three JA-Ile hydroxylases were all simultaneously silenced. These lines exhibited enhanced resistance only to BAW, but not to PTM, although levels of JA-Ile and its downstream induced defensive chemicals, including caffeoylputrescine, dicaffeoylspermidine, lyciumoside II, and the nicotianosides I, II, and VII, were all present at higher levels in PTM-infested than in BAW-infested irStCYP94B3s lines. Our results provide support for the hypothesis that StCYP94B3 genes are able to act as potential targets for the control of polyphagous insect pests in potato, and reveal that the oligophagous PTM has evolved an effective mechanism to cope with JA-Ile-induced anti-herbivore defenses. © 2022 Society of Chemical Industry.

Protection of Potatoes and Mortality of Wireworms (Agriotes obscurus) With Various Application Methods of Broflanilide, a Novel Meta-Diamide Insecticide.

Wireworms are primary pests of potatoes in Canada. Presently, the highly toxic organophosphate phorate (i.e., Thimet 20G) is the only effective insecticide in use in Canada. As such, there is an urgent need for novel alternative treatments that provide competitive tuber blemish protection and wireworm reduction with a safer human and environmental portfolio. Herein we evaluated broflanilide, a novel meta-diamide insecticide for both tuber protection and wireworm mortality. When evaluated in field trials in Agassiz, British Columbia over 6 yr, broflanilide applied as a seed piece treatment (SPT) to mother tubers at 1.5-2.0 g AI/100 kg seed (approx. 50 g AI/ha), or as an in-furrow spray (IFS) at 0.23-0.25 g AI/100 m row (approx. 25 g AI/ha) was as effective at reducing blemishes to daughter tubers by wireworms (Agriotes obscurus) as phorate (Thimet 20G at 3230 g AI/ha), bifenthrin (Capture 2EC IFS at 300 g AI/ha) and clothianidin (Titan ST at 312.5 g AI/ha). In addition, broflanilide SPT and IFS applied at the above rates reduced resident wireworms (in the field at the time of planting) by 95.4-99.0% and neonate wireworms (produced from eggs laid during the growing season) by 98.1-100%. Similar results were obtained when broflanilide IFS (nonsystemic) was paired with clothianidin SPT (systemic) for broad-spectrum potato insect pest control. Strategies for the use of broflanilide on wheat (e.g., Teraxxa F4) in rotation with potatoes (Cimegra), both registered in Canada in 2020 are discussed.

Evaluation of the impact of parasitoids in the management of potato pests in Senegal

Evaluation of the impact of parasitoids in the management of potato pests in Senegal

Selection of the most productive nutrient media for the cultivation of predatory nematodes

Modes of mass production of entomopathogenic nematodes isolated from various habitats of Akmola and Pavlodar regions were tested. As a result of the selection of nutrient media and cultivation conditions of entomopathogenic nematodes, the largest populations of nematodes (more than 100,000 young individuals/ml) were obtained on medium C11 containing yeast extract (23 g/l), egg yolk (13.5 g/l), and corn extract (40 g/l). On the 20th day of cultivation, the maximum concentration of viable nematodes was reached (123 856, 127 572, and 122 469 nematodes/ml for isolates AF 29, AF 57, and KP 76, respectively), which was maintained until the end of the experiments. During the process, the initial concentration of nematodes increased by more than 2 orders of magnitude. When working out the modes of mass production of nematodes on a semi-industrial scale, the populations of isolates AF 29, AF 57, and KP 76 in media amounted to 122 754, 131 784, and 126 521 nematodes per ml. The total volume of the resulting preparation was 50 liters. The obtained results are applicable in crop production in the fight against potato pests. \

Insecticidal potential of entomopathogenic nematodes of Northern Kazakhstan

The goal of this research experiment is to create a biological preparation based on predatory nematodes to control potato pests. 15 isolates of entomopathogenic nematodes were isolated: 13 were isolated from coniferous and mixed forests; 2 from soils of agricultural fields: 1 from a potato field, 1 from a field sown with perennial grasses. Nematodes were identified as Steinernematids based on the color of the corpses of larvae of Galleria mellonella and the morphology of males. Isolates of entomopathogenic nematodes from various habitats (forests, agricultural fields, grasslands) of Akmola and Pavlodar regions were isolated. Screening of isolates on the larvae of the seed nutcracker (Agriotes obscurus) was carried out. It is established that the wireworm is sensitive to all isolates. Of the 15 isolates tested, 12 of these isolates showed high mortality ability in relation to wireworm: about 50–70 % mortality in laboratory biotests; 3 isolates (AF 15, AF 22, and AS 36) could not cause more than 40 % of the average mortality of larvae. The screening results showed that the isolates AF 29, AF57, and KP76 are good isolates for further studies as a possible bioinsecticide agent against A. obscurus.

De Novo Transcription Responses Describe Host-Related Differentiation of Paracoccus marginatus (Hemiptera: Pseudococcidae).

Simple SummaryThe papaya mealybug, Paracoccus marginatus, is an invasive pest affecting many crop plants. It reproduces and spreads rapidly. They have historically been a pest of potato, Solanum tuberosum, but they have successfully adapted to infesting papaya, Carica papaya. When they feed on papaya, they survive and reproduce more and live longer than when they feed on potato. We do not yet know what biological adaptations they made in order to use this new host plant. We compared the RNA sequences of papaya mealybugs feeding on potato and papaya. A total of 408 genes are expressed differently depending on the host plant. Most of these genes are expressed less when feeding on potato than on papaya. They encode digestive enzymes, detoxifying enzymes, and ribosomes and some have reproductive functions. We further analyzed their known functions using the Kyoto Encyclopedia of Genes and Genomes. This showed that they include genes regulating digestion, detoxification, and longevity. We suggest that papaya is a more suitable host than potato, and that the decreased expression of particular genes may have important effects on the adaptation of the papaya mealybug to this alternative host plant.Paracoccus marginatus (Hemiptera: Pseudococcidae) is an invasive pest with a diverse host range, strong diffusion, and high fecundity. It has been observed that P. marginatus feeding on Carica papaya have a higher survival rate, fecundity, and longer lifespan than P. marginatus feeding on Solanum tuberosum, indicating their successful adaptation to C. papaya; however, the mechanisms underlying host plant adaptation remain unclear. Therefore, RNA-seq was performed to study the transcriptional responses of P. marginatus feeding on C. papaya and S. tuberosum plants. A total of 408 genes with significant differential expression were defined; most of them were downregulated in S. tuberosum, including those of digestive enzymes, detoxifying enzymes, ribosomes, and reproductive-related genes, which may result from the adaptation of the host to nutritional needs and changes in toxic chemical levels. Enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes showed that lysosome and longevity regulating pathways related to digestion, detoxification, and longevity were enriched. We suggest that C. papaya is a more suitable host than S. tuberosum, and downregulated target genes may have important effects on the adaptation of P. marginatus to host transfer.

Insights into the Use of Eco-Friendly Synergists in Resistance Management of Leptinotarsa decemlineata (Coleoptera: Chrysomelidae).

Simple SummaryThe discovery of insecticides requires time and has a high investment cost. However, injudicious use of insecticides has resulted in insect pest resistance and pest resurgence. These factors limit the market life of insecticides. To cope with this problem, synergists working as blockers of detoxification enzymes can provide a unique solution in resistance management. Owing to problems associated with chemical synergists, plant-based and RNAi-based synergists are much safer and easier to develop against insects. In fact, the Colorado potato beetle (CPB) has a unique detoxification mechanism due to its co-evolution with Solanaceous plants. This review is about how synergists can be used to deal with the resistance management of the CPB and will be helpful for researchers devising unique pest management strategies for other insect pests.The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is the most notorious insect pest of potato globally. Injudicious use of insecticides for management of this pest has resulted in resistance to all major groups of insecticides along with many human, animal health, and environmental concerns. Additionally, the input cost of insecticide development/discovery is markedly increasing because each year thousands of chemicals are produced and tested for their insecticidal properties, requiring billions of dollars. For the management of resistance in insect pests, synergists can play a pivotal role by reducing the application dose of most insecticides. These eco-friendly synergists can be classified into two types: plant-based synergists and RNAi-based synergists. The use of plant-based and RNAi-based synergists in resistance management of insect pests can give promising results with lesser environmental side effects. This review summarizes the resistance status of CPB and discusses the potential advantage of plant-based and RNAi-based synergists for CPB resistance management. It will motivate researchers to further investigate the techniques of using plant- and RNAi-based synergists in combination with insecticides.

Estimation of the potential geographical distribution of a new potato pest (Schrankia costaestrigalis) in China under climate change

Global food security is threatened by the impacts of the spread of crop pests and changes in the complex interactions between crops and pests under climate change. Schrankia costaestrigalis is a newly-reported potato pest in southern China. Early-warning monitoring of this insect pest could protect domestic agriculture as it has already caused regional yield reduction and/or quality decline in potato production. Our research aimed to confirm the potential geographical distributions (PGDs) of S. costaestrigalis in China under different climate scenarios using an optimal MaxEnt model, and to provide baseline data for preventing agricultural damage by S. costaestrigalis. Our findings indicated that the accuracy of the optimal MaxEnt model was better than the default-setting model, and the minimum temperature of the coldest month, precipitation of the driest month, precipitation of the coldest quarter, and the human influence index were the variables significantly affecting the PGDs of S. costaestrigalis. The highly- and moderately-suitable habitats of S. costaestrigalis were mainly located in eastern and southern China. The PGDs of S. costaestrigalis in China will decrease under climate change. The conversion of the highly- to moderately-suitable habitat will also be significant under climate change. The centroid of the suitable habitat area of S. costaestrigalis under the current climate showed a general tendency to move northeast and to the middle-high latitudes in the 2030s. The agricultural practice of plastic film mulching in potato fields will provide a favorable microclimate for S. costaestrigalis in the suitable areas. More attention should be paid to the early warning and monitoring of S. costaestrigalis in order to prevent its further spread in the main areas in China’s winter potato planting regions.

Management of major insect pests of potato during rabi season using newer insecticide molecules

The field experiments were carried out in a randomized block design during rabi seasons of 2016-17 and 2017-18, to evaluate the effect of newer insecticide molecules against insect and mite pests of potato during rabi season in Karnataka, India. There were 10 treatments including an untreated check and replicated thrice. Kufri Pukhraj was used as a test variety in a plot size of 3 × 4 m with a spacing of 60 × 20 cm. Two sprays were taken up, the first being given 30 days after sowing and another 15 days later based on the economic threshold level of the pests. Among the insecticides evaluated, cyantraniliprole 10 OD @ 0.20 ml/l proved its excellence against shoot borer and defoliator by recording 65.27 and 72.69 per cent protection, respectively which was followed by spinosad 45 SC @ 0.20 ml/l (51.96 and 62.40%, respectively). Whereas in the case of sucking pests viz., aphid, leafhopper and whitefly, diafenthiuron 50 WP @ 1.00 g/l proved its superiority by documenting 78.00, 77.27 and 57.79 per cent protection, respectively. The highest percent protection over control against thrips was afforded by spinosad 45 SC @ 0.20 ml/l (67.54 %) followed by cyantraniliprole 10 OD @ 0.20 ml/l (58.62 %) and emamectin benzoate 5 SG @ 0.25 g/l (49.70 %). In respect of mites, the treatment with spiromesifen 22.9 SC @ 1.00 ml/l registered the highest protection of 70.38 per cent. The treatment cyantraniliprole 10 OD @ 0.20 ml/l recorded highest net returns of Rs. 2,65,897/ha with benefit-cost ratio of 7.47 followed by spinosad 45 SC @ 0.20 ml/l (Rs. 2,38,558/ha and 6.60) and emamectin benzoate 5 SG @ 0.25 g/l (Rs. 2,34,400/ha and 6.72).

Meloidogyne Incognita Management using Fumigant and Non-fumigant Nematicides on Sweet Potato.

Southern root-knot nematode (SRKN, Meloidogyne incognita) is a major pest of sweet potato, and nematicides are needed to manage this nematode. The objectives of this study were to assess the efficacy of fluazaindolizine, a new non-fumigant nematicide, in comparison with the fumigant nematicide 1,3-dichloropropene (1,3-D) and non-fumigant nematicides fluopyram and oxamyl for (1) SRKN management, (2) impacts on free-living nematodes, and (3) sweet potato yield in field trials. Among all nematicides, 1,3-D at 84 kg/ha most consistently (2 of 3 years) managed SRKN soil populations and improved yield. Fluazaindolizine at 2.24 kg/ha and fluazindolizine at 1.12 kg/ha plus oxamyl at 2.14 kg/ha managed SRKN populations and improved yield in 1 of 3 years, whereas fluazaindolizine alone at 1.12 kg/ha only decreased SRKN populations. Fluopyram at 238 g/ha did not affect SRKN or yield. Nematicide application also had non-target effects on free-living nematodes with 1,3-D reducing abundances relative to untreated most frequently (2018 and 2020), but other nematicides also reducing free-living nematode abundances in 2020. In summary, 1,3-D is the most consistent option for SRKN control on sweet potato, but fluazaindolizine, oxamyl or combinations of the two products can also be effective.

Efficacy of Soil Insecticides Against Sucking Pests of Potato

Field experiments were conducted at three locations for two seasons, 2018 to 2020 to evaluate the efficacy of soil insecticides against sucking pests of potato. Lowest cumulative mean number of whiteflies was observed with fipronil 0.3G @ 25 kg/ ha, and it was on par with its dose of 20 kg/ ha, cartap hydrochloride 4G @ 20 and @ 25 kg/ ha; overall reduction in whiteflies over control ranged between 56.70 and 59.04% at Jalandhar; 53.17 to 60.89% at Modipuram, and 57.33 to 62.40% at Gwalior. Similar trends were noted for aphids, leaf hoppers and thrips. Based on tuber yield and benefit cost ratio, cartap hydrochloride 4G @ 20 kg/ ha (2.62) and fipronil 0.3G @ 20 kg/ ha (2.47) were found to be the most effective against the sucking pests of potato. Hence, both these can be recommended in potato in place of phorate 10G.

Bottom-up effects of drought on the growth and development of potato, Leptinotarsa decemlineata Say and Arma chinensis Fallou.

Global climate change will result in increasingly arid weather that will have a significant impact on agriculture. The occurrence dynamics of plants, phytophagous insects and their natural enemies under drought conditions have attracted much attention. The consequences could be useful for controlling insect herbivores. Leptinotarsa decemlineata (Say) is one of the most important pests of potato, and causes serious damage to potato production. Arma chinensis (Fallou) is a parasitoid of L. decemlineata. However, how drought will affect tritrophic interactions between potato and these insects remains unknown. In this experiment, L. decemlineata and A. chinensis were released onto potato plants under water stress. Thereafter, plant height, stem diameter and yield of potato, growth and reproduction of L. decemlineata, and the longevity of A. chinensis adults were periodically recorded. The results showed that drought had crucial effects on height, stem diameter and yield of potato (p < 0.05); it also had a significant impact on pre-oviposition period, oviposition days, fecundity and life table parameters in L. decemlineata (p < 0.05). Moreover, drought significantly reduced the longevity (p < 0.05) and survival rate of A. chinensis adults. The longevity of adult A. chinensis was only 29.00 ± 3.00 days and the harvest rate of L. decemlineata adults was only 1.42% ± 0.07% under drought treatment. In this experiment, we evaluate the bottom-up effects of drought on tritrophic interactions involving potato, L. decemlineata and A. chinensis, and discuss the implications of the findings for integrated pest management programs involving the pest. Promising future research directions are proposed. © 2022 Society of Chemical Industry.

Surveillance for potato tuber moth, Phthorimaea operculella Zeller (Lepidoptera: Gelichiidae) in Kolar and Chikkaballapur district of Karnataka

Potato tuber moth (PTM), Phthorimaea operculella Zeller has become one of the most serious insect pests of potato (Solanum tuberosum L.) around the world, including in India. Field studies were conducted against PTM in Rabi seasons during 2019-20 in four and two taluks of Kolar and Chikkaballapur districts of Karnataka, respectively to understand the extent of foliage damage and leaf mines. Mean per cent infestation of PTM and number of mined leaves per plant during Rabi season of survey were highest with 4.47% and 8.31 mined leaves in Kolar district and it was least in Chikkaballpur district (2.51% and 2.95), respectively. Number of mines per plant was observed lowest (5.09) in Kolar district compared to Chikkaballapur district with 5.24 mines per plant. The above damage parameters like per cent PTM infestation and number of mined leaves per plant were not differed significantly whereas number of mines per plant was significantly different in Chikkaballapur district. On the other hand, all the damage parameters were significantly differed in Kolar districts during the survey in Rabi season 2019-20. In recent years, the temperature has been steadily rising due to climate change, and it is predicted that the occurrence of the PTM will continue to increase in the future. Therefore, the development of control technologies and intensive monitoring will be necessary for stable potato production as well as potato post-harvest.

Pendampingan Pengenalan Musuh Alami Hama Potensial Pada Tanaman Kentang Di Sembalun

Interventions in the use of technology to farmers as an alternative in Pest Management in potato cultivation are highly expected by farmers in the Sembalun area. Therefore, it is worth trying its utilization on potato crops to control important pests that attack. The method used in this activity is the Action Research Method by applying the Participatory Action Program approach from participants through discussions, and group work on all activities. The results of the group discussion showed that the group members had largely not recognized the types and functions of natural enemies in Potato Pest Management. After joint observations accompanied by the team, participants actually knew the types of natural enemies, both predators, and parasitoids, but they did not know the role of natural enemies in the agroecosystem. After finishing the meeting, the group realized the importance of maintaining the presence of natural enemies of pests in the potato agroecosystem so that the use of pesticides, which had been the main control technique for pests, could be reduced. Thus, it is hoped that the potato farming business in Sembalun will increase profits and produce environmentally friendly products

Management of potato cyst nematodes with special focus on biological control and trap cropping strategies.

Potato cyst nematodes (PCNs; Globodera spp.) are one of the most difficult pests of potato to manage worldwide. Indiscriminate use of pesticides and their hazardous effects discourage the use of many chemicals for the management of PCNs. As a result, biological control agents and trap crops have received more attention from growers as safer ways to manage PCNs. The biological control agents such as Pochonia chlamydosporia, Purpureocillium lilacinum, Trichoderma spp., Pseudomonas fluorescens, Bacillus spp., Pasteuria spp., and others are recognized as potential candidates for the management of PCNs. Moreover recently, the use of trap crop Solanum sisymbriifolium also showed promise by drastically reducing soil populations of PCNs. Integration of these management strategies along with other practices including identification, conservation, and multiplication of native antagonists, will facilitate efficient management of the PCNs in potato cropping system. Some of the promising research approaches that are being used against PCNs are addressed in this review. © 2022 Society of Chemical Industry.

Establishment of Beauveria bassiana as a fungal endophyte in potato plants and its virulence against potato tuber moth, Phthorimaea operculella (Lepidoptera: Gelechiidae).

The potato tuber moth, Phthorimaea operculella, is the most damaging potato pest in the world and is difficult to control as the larvae are internal feeders in the foliage and tubers. Entomopathogenic fungi that colonize plants as endophytes have lethal and sublethal pathological effects on insect pests. We show that Beauveria bassiana colonizes the aerial parts of potato plants endophytically after inoculation through soil drenching. Endophytic B. bassiana persisted in potato foliage for more than 50days postinoculation. Bioassays indicated that foliage of B. bassiana-inoculated potato plants were pathogenic against larvae of P. operculella. Sublethal experiments indicated that B. bassiana negatively affected the growth, development, and reproduction of P. operculella. Development experiments showed that the weight of P. operculella pupae reared on B. bassiana-colonized potato plants (4.25mg) was significantly less than that of those reared on uninoculated control plants (8.89mg). Compared with newly eclosed larvae fed on control plants, those fed on B. bassiana-inoculated plants had significantly lower survivorship, with only 17.8% developing to the adult stage. Oviposition of P. operculella females reared on B. bassiana endophytically colonized plants was significantly lower (35 eggs/female) than of those reared on uninoculated plants (115 eggs/female). This study demonstrates that endophytic B. bassiana can be a potential biological control agent for the control and management of P. operculella. Comparing pupal weights of P. operculella reared on potato plants inoculated with the B. bassiana strain GZGY-1-3 and on untreated control plants, pupae from the control plants were significantly heavier than those from treated plants.

Cry3Aa Toxin Is Not Suitable to Control Lepidopteran Pest Spodoptera littoralis (Boisd.).

The toxicity of the Bacillus thuringiensis (Bt) toxin Cry3Aa—originally used against the main potato pest, the Colorado potato beetle, Leptinotarsa decemlineata—was verified on this species and then evaluated against the Egyptian armyworm, Spodoptera littoralis, which is a pest of several economically important plants. Larvae of S. littoralis were fed a semi-artificial diet supplemented either with a recombinant or with a natural Bt toxin Cry3Aa and with the genetically engineered (GE) potato of variety Superior NewLeaf (SNL) expressing Cry3Aa. Cry3Aa concentration in the diet and the content in the leaves were verified via ELISA (enzyme-linked immunosorbent assay) and HPLC (high-performance liquid chromatography) during and at the end of the experiments. The biological effectiveness of the coleopteran-specific Cry3Aa with previous reports of activity against S. littoralis was tested on five different populations of S. littoralis larvae by monitoring 13 parameters involving development from penultimate instar, weight, the efficiency of food conversion to biomass, ability to reproduce, and mortality. Although some occasional differences occurred between the Cry3Aa treatments and control, any key deleterious effects on S. littoralis in this study were not confirmed. We concluded that the Cry3Aa toxin appears to be non-toxic to S. littoralis, and its practical application against this pest is unsuitable.