Pest Of Sugar Beet Research Articles

Parasitoid flies of corn and sugar beet pests in Kermanshah and Hamedan provinces (Diptera: Tachinidae)

Parasitoid flies of corn and sugar beet pests in Kermanshah and Hamedan provinces (Diptera: Tachinidae)

Registration of sugar beet genetic stocks FC308 and FC309

AbstractSugar beet (Beta vulgaris L.) genetic stock lines FC308 (Reg. no. GS‐14, PI 701378) and FC309 (Reg. no. GS‐13, PI 700990) are two highly homozygous and phenotypically homogenous sources of resistance to two separate sugar beet pests. FC308 is resistant to sugar beet cyst nematode (SBCN) but is susceptible to Fusarium yellows (FY), whereas FC309 is FY resistant but SBCN susceptible. These two populations were developed by the USDA‐ARS in Fort Collins, CO, derived from unreleased USDA‐ARS Salinas germplasm lines 7927‐4‐308 and 7927‐4‐309. Multiple field and greenhouse trials for FY and nematode resistance confirmed the homogeneous phenotypic responses of both lines for each disease. To enable molecular breeders to rapidly screen proprietary markers in silico on these lines, gene space assemblies for individual plants from each line were also developed and are being released alongside these genetic stocks. Genome sequencing of individual plants from each line, as well as pooled sequencing of sub‐populations of both lines, indicated fixation of a previously reported genetic variant linked to SBCN resistance in FC308. However, two previously reported variants linked to Fusarium resistance appear to be unlinked to the resistance found in FC309. Collectively, these two new sugar beet genetic stock lines should prove useful as sources of resistance to FY and SBCN, as model genetic backgrounds for studying plant–pathogen interactions, and for mapping the causal resistance genes present in these lines.

Efficacy of Bacillus thuringiensis Strain 407 versus Synthetic Pesticides in Controlling Sugar Beet Pests under Open Field Conditions

Efficacy of Bacillus thuringiensis Strain 407 versus Synthetic Pesticides in Controlling Sugar Beet Pests under Open Field Conditions

Integrated Biological Control of the Sugar Beet Weevil Asproparthenis punctiventris with the Fungus Metarhizium brunneum: New Application Approaches.

The mass occurrence of the sugar beet weevil (Asproparthenis punctiventris, previously Bothynoderes punctiventris) has been endangering sugar beet cultivation in Austria for centuries. Exacerbated by climatic and political changes (warmer, drier spring and limited access to chemical pesticides), new approaches are needed to counter the problem. The aim of our work was to test whether the bioinsecticide Metarhizium brunneum Ma 43 (formerly M. anisopliae var. anisopliae BIPESCO 5/F52) can be used as a sustainable plant protection product against the sugar beet weevil. Our goal was to control the pest in all its development stages through multiple applications. Therefore, GranMetTM-P, a granular formulation of M. brunneum Ma 43, was applied in spring to establish the fungus in the soil, whereas GranMetTM-WP, a liquid formulation of the production strain, was used in early summer on trap ditches and leaves to target the adult weevils. Soil and plant samples as well as weevils were collected during the planting season from the trial sites to evaluate the development of the fungus and the mycosis of the treated weevils. In addition, data on hibernating weevils and their emigration from untreated field sites was collected. In all field sites, the Metarhizium spp. abundance increased above the background level (<1000 CFU g-1 soil dry weight) after application of the product. With an increasing number of treatments per plot, and thus an increased contact possibility between pest and the fungus, a rise in the mycosis rate was observed. In conclusion, the various Metarhizium application strategies, which are already available or in testing, must be implemented to ensure control in both old and new sugar beet fields. Metarhizium is a further asset in the successful control of this sugar beet pest.

Suitability of Amaranthaceae and Polygonaceae species as food source for the sugar beet weevil Asproparthenis punctiventris Germar

This study explores the food plant spectrum of the sugar beet weevil (Asproparthenis punctiventris Germar; Coleoptera: Curculionidae), one of the most important pests of sugar beet (Beta vulgaris subsp. vulgaris Altissima group). It examines the potential of various weeds and other plants to maintain populations of A. punctiventris adults and larvae outside sugar beet fields. To this end, leaf consumption of females and males on twelve Amaranthaceae and six Polygonaceae species was compared over a 24-h period in a laboratory environment. Both sexes consumed the greatest amount of leaf mass from Beta spp. and on average about a third less from Atriplex spp., indicating that these plants have the highest nutritional value for A. punctiventris. Weevils consumed between 30 and 60% of the amount of A. retroflexus and Chenopodium spp. than they fed on sugar beet leaves. Like Spinacia oleracea (Amaranthaceae), plant species of the Polygonaceae family were hardly or not at all fed on. Mated females generally consumed more leaf mass than unmated, especially from Chenopodium spp. and A. retroflexus, i.e. plants with low feeding value. Experiments with potted plants revealed that the most and heaviest 4th instar larvae developed on sugar beet, while fewer individuals with lesser weight were found on B. vulgaris subsp. maritima and A. hortensis. Very few larvae were able to develop on C. album, and none on A. retroflexus. To prevent promotion of pest population, special attention should be paid to the control of weeds from the Amaranthaceae family in sugar beet growing areas.

INVESTIGATION OF THE IMPACT OF THE PROTECTION SYSTEM ON THE LIMSTED OF SUGAR BEET PESTS ON THE RIGHT BANK FOREST STEPP

The article highlights the theoretical generalization and a new solution to the problem, which is to develop and substantiate elements of the system of protection of sugar beet from pests and control of their numbers in Vinnytsia region, which is based on number when using insecticides for seed treatment and spraying crops with chemical and biological drugs. The species composition of the harmful entomofauna of sugar beet has been specified and 14 species of pests have been identified, including 9 dominant species. It was determined that phytophagous plants of the Coleoptera series dominate in the taxonomic structure of the harmful entomocomplex in sugar beet crops (Agriotes obscurus L., Agriotes lineatus L., Melolontha melolontha L. – 34.3%, Homoptera (Aphis fabae Scop., 17%) (Scotia segetum Schiff., Heliothis viriplaca Hfn.) – 16,3% and Diptera (Pegomyіa betae Curt.) – 6,3%, among which there are both polyphagous and specialized species, from the class Diplopoda – 22,5%. The effectiveness of modern insecticides against the dominant pests of sugar beet is evaluated and the methods of their application are optimized. It was found that the Cruiser 350 FS provided the greatest technical efficiency in the treatment of sugar beet seeds against Aphis fabae Scop. – 95,4%. The technical efficiency of other disinfectants was in the range of 76,9–84,6%. Treatment of sugar beet seeds against seed pests with insecticide Poncho 600 FS, TH reduced the number of phytophages by 86,5%, Cruiser 350 FS, t.k.s. – 78.0%, Gaucho 70 WS, pp – 75,4%, Emesto Quantum 273,5 FS, TH – 63,2%. Treatment of sugar beet seeds with insecticidal pesticides Gaucho 70 WS, z.p. (60.0 kg/t), Emesto Quantum 273.5 FS, TH (0.3 l/t), Poncho 600 FS, TH (3.0 l/t) and Cruiser 350 FS, t.k.s. (15.0 l/t) ensured the preservation of the yield of 8,3–12,6 t/ha.

Evaluation of the emergency authorisations granted by Member State Croatia for plant protection products containing thiamethoxam

The European Food Safety Authority (EFSA) was requested by the European Commission to provide technical assistance in accordance with Article 53(2) of Regulation (EC) No 1107/2009 to examine the emergency authorisations granted in 2020 by the competent national authority in Croatia for plant protection products containing the neonicotinoid active substances (a.s) clothianidin, imidacloprid or thiamethoxam for uses on sugar beet which were restricted when all outdoor uses were prohibited in May 2018. EFSA was asked to assess whether the granting of this emergency authorisation and its wide scope was necessary because of danger which cannot be contained by any other reasonable means. In this context, EFSA collected and evaluated the information in relation to the emergency authorisation for thiamethoxam in Croatia in line with the EFSA insecticide protocol developed in the framework of a mandate concerning the application of Article 4(7) of Regulation (EC) No 1107/2009. The current technical report summarises the outcome of the evaluation of four crop/pest combinations considered in the evaluation provided by Croatia for authorisations in 2020. The evaluation demonstrated that for the tested pests of sugar beet (Agriotes sp., Atomaria linearis, Bothynoderes punctiventris and Chaetocnema sp.) no sufficient alternative a.s. to thiamethoxam are currently authorised in Croatia. The evaluation included an assessment of non-insecticide alternatives for the presented uses. The possible non-insecticide alternative methods listed to control sugar beet insects in Croatia are crop rotation and well-balanced fertilisation. These practices are applied in more than 50% of the acreage of the crop and are only moderately effective against pests. An assessment for aphids (Aphididae) was not presented.

Evaluation of the emergency authorisations granted by Member State Poland for plant protection products containing imidacloprid, thiacloprid or thiamethoxam

The European Food Safety Authority (EFSA) was requested by the European Commission to provide technical assistance in accordance with Article 53(2) of Regulation (EC) No 1107/2009 to examine the emergency authorisations granted in 2020 by the competent national authority in Poland for plant protection products containing the neonicotinoid active substances (a.s.) clothianidin, imidacloprid, thiamethoxam or thiacloprid for uses on sugar beet which were restricted when all outdoor uses were prohibited either in May 2018 or in the case of thiacloprid a decision on its non-renewal of approval coming into force in August 2020. EFSA was asked to assess whether the granting of these emergency authorisations and their wide scope was necessary because of danger which cannot be contained by any other reasonable means. In this context, EFSA collected and evaluated the information in relation to the emergency authorisation for imidacloprid thiacloprid and thiamethoxam in Poland in line with the EFSA insecticide protocol developed in the framework of a mandate concerning the application of Article 4(7) of Regulation (EC) No 1107/2009. This technical report summarises the outcome of the evaluation of two crop/pest combinations considered in Poland in 2020. The evaluation demonstrated that for both tested pests of sugar beet (Agrotis spp. & Bothynoderes punctiventris) no sufficient alternative active substances to neonicotinoids are currently authorised in Poland, in order to provide alternative modes of action (MoA). The evaluation included an assessment of non-insecticide alternatives for the presented uses. Cultural methods (soil tillage, isolation between fields, early sowing date, sowing rate increase, weeding out including field bounds, keeping higher soil moisture) are considered as of low to moderate efficacy and not always feasible. These methods are used in a small scale (i.e. applied on less than 10% of the acreage of the crop). Biocontrol with parasitic nematodes is considered as moderately effective.

The First Record of Tortoise Beetle Damage to Sugar Beet in the UK: Is Global Warming Responsible?

The authors thought they had experienced everything that the sugar beet crop could throw at them from a pest point of view after almost 40 years of working with the sugar beet industry. It was therefore very exciting to be confronted with a highly unusual pest this summer, so unusual that its presence in high numbers causing significant damage to a sugar beet crop in Norfolk in August 2021, is the first record of such damage in the UK. The pest was the exotic tortoise beetle, Cassida nebulosa, which the sugar beet bible, Pests, Diseases and Disorders of Sugar Beet, published by the International Institute de la Recherches Betteraves (IIRB), describes as rare, and never important in northern Europe. Indeed, this species has never, in our memory, been recorded before as a pest in sugar beet in the UK, only a very rare presence. Dewar and Cooke (2006) stated in their review of pest problems in sugar beet the UK, that crop damage by tortoise beetles never occurs in western Europe, but can be severe in warmer Mediterranean regions and in Russia.

The Efficacy of Seed Treatments on Major Sugar Beet Pests: Possible Consequences of the Recent Neonicotinoid Ban

Sugar beet production remains unprotected after the ban on neonicotinoids, while pest pressure is increasing. Although the organic approach to agriculture is highly welcomed, the question remains whether it will be possible to grow sugar beet without pesticides. The aim of this study is to determine the efficacy of seed treatments with neonicotinoids on the main sugar beet pests, to determine the susceptibility of the pests under the specific climatic conditions and to discuss possible consequences of the ban of neonicotinoids on the future of sugar beet production in southeast Europe. The study was conducted in two different climatic regions in Croatia in two consecutive years. The tested variants were: seed coated with imidacloprid, seed coated with a combination of thiamethoxam and teflutrin and untreated control. Our results showed that seed coatings with imidacloprid and thiamethoxam provided satisfactory protection against wireworms, flea beetles and sugar beet weevils at low population pressure. These pests are regular pests of sugar beet in southern and eastern Europe and therefore need to be controlled. Caterpillars and aphids were present in low populations, so the efficacy of the insecticides tested cannot be determined with certainty. A further research program is needed to find alternative solutions and develop easily implementable strategies for all sugar beet pests. We would propose an authorization of neonicotinoids for seed treatment of sugar beet in the regions with high infestation pressure of the main sugar beet pests.

Induction of diapause by clock proteins period and timeless via changes in PTTH and ecdysteroid titer in the sugar beet moth, Scrobipalpa ocellatella (Lepidoptera: Gelechiidae).

The sugar beet moth, Scrobipalpa ocellatella (Boyd), one of the most severe sugar beet pests, causes quantitative and qualitative yield losses late in the autumn. Previously, it was shown that low temperature and short-day photoperiod together cause diapause induction in pupae. Here, the interaction of the critical elements of the diapause induction, including the period (PER), timeless (TIM), prothoracicotropic hormone (PTTH), and ecdysteroid titer, were investigated. Immunohistochemistry results showed that the number of period immunoreactivity (PER-ir) and TIM-ir cells in nondiapause pupae (NDP) was lower than in the brain of the diapause pupae (DP). Moreover, the number of PER-ir and TIM-ir cells in the protocerebrum and optic lobe (OL) of NDP was lower than DP. Moreover, lower PTTH content in the brain and hemolymph of DP was confirmed by competitive enzyme-linked immunosorbent assay. Enzyme immunoassay showed a lower 20-hydroxyecdysone (20E) titer in the hemolymph of the DP compared with the NDP. Within a short-day condition, PER and TIM titers increased in the brain leading to decreasing PTTH titers in the brain and hemolymph that caused decreasing 20E titer in the hemolymph, leading to the induction of diapause. This study suggests that PER and TIM could be one of the brain factors that play an essential role in regulating diapause in S. ocellatella.

Phytosanitary state of sugar beet agrocenosis in 2019 and forecast of the number of phytophages in the current year

Purpose. To generalize and analyze the data provided by state phytosanitary inspections of the Department of Phytosanitary Safety of the State Veterinary Service of Ukraine on the dynamics of development of the main pests in sugar beet stands in Ukraine in 2019 and to forecast their appearance and possible damage in the current year.
 Methods. Field, accounting, analytical.
 Results. In 2020, sugar beet crops may be damaged by beetroot weevil, grey beetroot weevil, beet stalk borer, beet flea, beet leaf miner, beetroot aphids and other pests. According to the results of autumn field monitoring, 57% of beet areas was colonized by beetroot beetle with an average number per 1 m2 of 0.5–1.0 (beetles, pupae) with the maximum number of 2–9 in Volyn, Kyiv, Poltava, Cherkasy, Chernihiv, Zhytomyr, Sumy regions. During the autumn excavations, the beetles in the population were 75%, pupae 20% and larvae 5%. In respect to grey beetroot weevil, it made the greatest damage to sugar beet crops in Kyiv, Poltava, Kharkiv, Sumy, Volyn, Kirovohrad, Khmelnytsk, and other regions, where it colonized 24–100% of stands with an average number of 0.1–0.6 with a maximum of 0.6–1.0. It damaged, on average, 2–6% of stands with the maximum of 7–12%. Autumn monitoring of the pest found a significant number of the pest in all beetroot regions with an average number of 0.5–0.7 with the maximum of 1.0–4.0. In addition, autumn monitoring revealed a significant number of beet stalk borer (average 0.1–0.7, maximum 0.7–1.0 specimens) in farms of Poltava and Cherkasy regions. Beet tortoise beetles were detected on 10–100% of the monitored area with an average number of 0.1–0.4, which is lower than in long-term observations. In the majority of areas, goosefoot tortoise beetles dominated (33–100%). On average, the ratio was 54% of goosefoot and 46% of beet root tortoise beetles. The wintering stock of beet beetle was slightly lower than in the last year and amounted to an average of 14–54, with the maximum in Vinnytsia, Rivne, Khmelnytskyi regions (76–100). Autumn inspections of host plants (red bilberry, snowball tree, jasmine) revealed 12–36, maximum 150 wintering eggs of leaf aphids per 1 meter of a branch. The wintering stock of beet leaf miner was 0.8–1.8, somewhere 2.9 (in Ternopil, Vinnytsia Khmelnytsk regions), which is at the level of the last year’s numbers. 
 Conclusions. The wintering stock of harmful sugar beet insects exceeds the generally accepted economic thresholds for harmfulness. The timely prognosis of the development and reproduction of sugar beet pests and the application of a complex of organizational, economic, biological and chemical measures to control their numbers will create conditions for the preservation of root harvest, improving root quality and reduce unreasonable pollution of the environment with chemicals.

Role of the Rove Beetle, Paederus memnonius (Erichson) (Coleoptera : Staphylinidae) in Controlling Certain Sugar Beet Pests for the First Time in Egypt

Role of the Rove Beetle, Paederus memnonius (Erichson) (Coleoptera : Staphylinidae) in Controlling Certain Sugar Beet Pests for the First Time in Egypt

Neonicotinoid Residues in Sugar Beet Plants and Soil under Different Agro-Climatic Conditions

European sugar beet was mostly grown from seeds treated by neonicotinoids which provided efficient control of some important sugar beet pests (aphids and flea beetles). The EU commission regulation from 2018 to ultimately restrict the outdoor application of imidacloprid, thiamethoxam, and clothianidin could significantly affect European sugar beet production. Although alternative insecticides (spinosad, chlorantraniliprole, neem) are shown to have certain effects on particular pests when applied as seed treatment, it is not likely that in near future any insecticide will be identified as a good candidate for neonicotinoids’ substitution. The aim of this research is to evaluate residue levels (LC-MS/MS method) of imidacloprid and thiamethoxam applied as seed dressing in sugar beet plants during two growing seasons in fields located in different agro-climatic regions and in greenhouse trials. In 2015, 25 to 27 days post planting (PP) maximum of 0.028% of imidacloprid and 0.077% of thiamethoxam were recovered from the emerged plants, respectively. In 2016, the recovery rate from the emerged plants 40 days PP was 0.003% for imidacloprid and 50 days PP was up to 0.022% for thiamethoxam. There were no neonicotinoid residues above the maximum residue level in roots at the time of harvesting, except in case of samples from thiamethoxam variant collected from greenhouse trials in 2016 (0.053 mg/kg). The results of this research lead to the conclusion that the seed treatment of sugar beet leaves minimal trace in plants because of the complete degradation while different behavior has been observed in the two fields and a glasshouse trial regarding the residues in soil. Dry conditions, leaching incapacity, or irregular flushing can result in higher concentrations in soil which can present potential risk for the succeeding crops. The results of our study could provide additional arguments about possible risk assessment for seed treatment in sugar beet.

Optimizing a pheromone lure for the sugar beet root maggot fly, Tetanops myopaeformis

AbstractWe previously described a putative aggregation pheromone in adults of the sugar beet root maggot, Tetanops myopaeformis (von Röder) (Diptera: Ulidiidae), comprising nine compounds identified from males. Here, we conducted a series of experiments aimed at simplifying the blend of compounds necessary to achieve attraction as well as determining the dose that maximizes captures when formulated into an attractant lure. In all experiments, females showed stronger and more consistent evidence of attraction than males. White sticky traps baited with different blends of pheromone compounds that included the major component, (R)‐(−)‐2‐nonanol, showed significantly higher female captures relative to those baited with blends that excluded the major component. (R)‐(−)‐2‐nonanol alone was at least as effective as any blend that included this compound with other minor pheromone components. Lures using racemic 2‐nonanol were as effective as the (R) enantiomer for both females and males, with some evidence of weak attraction to the (S) enantiomer (which is not produced by males) observed as well. Maximum capture rates using racemic 2‐nonanol were estimated to occur with doses of ca. 795.5 and 621.6 mg for females and males, respectively. Addition of 2‐nonanol lures to standard orange sticky stake traps currently used to monitor flies increased captures of both sexes. The pheromone lure developed here could improve trapping efficiency of current monitoring programs for T. myopaeformis and may also be used to develop other management tools for this important pest of sugar beet.

Genetic differentiation and diversity of sugarbeet germplasm resistant to the sugarbeet root maggot

AbstractGermplasm lines with resistance to the sugarbeet root maggot (SBRM) have been developed and released to the public, providing a means to generate hybrids with resistance against the most devastating insect pest of sugarbeet in North America. Effective use of this germplasm, however, requires knowledge of relative strengths of SBRM resistance between lines and knowledge of the diversity and genetic relationships between germplasm. Therefore, field studies comparing SBRM resistance of four released SBRM-resistant germplasm lines (F1015, F1016, F1024 and F1043), a SBRM-resistant parent (PI 179180) and an unreleased SBRM-resistant population (F1055) were performed, and genetic analysis of the diversity and relationships between SBRM-resistant germplasm and their available parents was conducted using simple sequence repeat (SSR) markers. Under natural SBRM infestations, resistant germplasm exhibited significantly less SBRM damage than a susceptible control, with similar, high levels of resistance in F1016, F1024, F1043, F1055 and PI 179180 and lower resistance in F1015. SSR analysis revealed genetic similarities between F1016, F1024 and F1055, while F1015 and F1043 were genetically distinct from these lines. Among resistant genotypes, F1015 and F1043 exhibited greatest and least within-line genetic diversity, indicating greater and lesser inbreeding for F1043 and F1015, respectively. Similarities in damage ratings and genetics for F1016, F1024 and F1055 indicate that these lines are likely to be equally effective at introducing SBRM resistance into elite populations and in combining ability. In contrast, F1043, with its unique parentage and genetic dissimilarity from other resistant lines, provides a genetically distinct, but similarly effective, source of SBRM resistance.

Grandisol as an attractant for the sugar beet pest Bothynoderes affinis and data on other Lixinae species

AbstractAs a result of field tests in Bulgaria and Hungary, cis‐2‐isopropenyl‐l‐methylcyclobutane ethanol (racemic grandisol) is reported for the first time as an attractant for Bothynoderes affinis (Schrank) (Coleoptera: Curculionidae, Lixinae), a member of the pest weevil complex of sugar beet. Dose–response experiments in the field using Csalomon TAL (modified pitfall) traps (Plant Protection Institute, CAR HAS, Budapest, Hungary) showed that catches of B. affinis adults increased with increasing attractant dose. In a subsequent experiment studying the effect of trap color (white, blue, yellow, fluorescent yellow, and transparent) all traps with the lure caught more than non‐baited control traps, and the highest number of adults was recorded in transparent and yellow baited traps. Trap color had a significant effect on the number of B. affinis females captured. Transparent TAL traps baited with 1–10 mg grandisol applied on rubber dispensers are recommended for the detection and monitoring of B. affinis. In addition to the target species, 17 other Lixinae species were captured during the field experiments, demonstrating for the first time the possible role of grandisol in the chemical communication systems of some of these species. A second locality of Lixus punctiventris Boheman (Lixinae, Lixini) in Bulgaria is reported. TAL traps baited with grandisol might be a useful tool for surveying Lixinae diversity in different biotopes.

Differentiate between Sugar Beet (Beta vulgaris L.) Genotypes Resistance to Root-knot Nematode, (Meloidogyne incognita) by Molecular Markers

The application of molecular methods as complementary or alternative methods can help identifying the plants containing the resistance gene at genotypic level. Therefore, DNA markers can be useful tools for selecting resistant genotypes and can save the evaluation time and improve the precisions. Selection takes productive and genetic lines resistant to nematodes have been known in sugar beet genotypes by Polymerase chain reaction (PCR). Sugar beet (Beta vulgaris L.)is the greatest vital crops that standing following to sugar cane as sugar crop in the world, later it produces about 20 % of sucrose production annually in the world. In Egypt, Sugar beet is cultivated in 523188 faddans with an average production of 20.7 tons per faddan. Recently, reclaimed desert irrigated lands at West Nubaryia and El-Bostan regions has shown that sugar beet can be successfully grown under sandy soil area condition and its considered as the extended area for sugar beet production in Egypt. The most serious problem against sugar beet extension in new lands is root-knot nematode, Meloidogyne incognita and Meloidogyne javanica which were reported as major nematode pests of sugar beet in Egypt. Importance of employed resistance nematode sugar beet genotypes (cultivars/hybrids) in infested areas has a great concern.The present study was carried out during the growing season 2015 - 2016 at pots experiment in Sabahia Agricultural Research Station, Alexandria, Egypt, for evaluating the reaction of seventeen sugar beet genotypes against the most serious nematode, (Meloidogyne incognita). The seventeen sugar beet genotypes tested in this test were twelve sugar beet commercial varieties, three sugar beet inbred lines and two sugar beet breeding materials. Computed damage index classified the seventeen sugar beet genotypes into five categories according to the varietal assessment. (Four were resistant(R), three were moderately resistant (MR), six were tolerant (T), two were susceptible (S) and two were hyper susceptible (HYS)). The results for conventional PCR indicated that genes of Hs1pro-1and HSPRO2 shows resistance to, (Meloidogyne incognita) beside the known function of these genes as resistant against cyst nematode (Heterodera schachtii). Mi-1.2 gene consider resistance to root knot nematode (Meloidogyne incognita) was found in (Mi-3) inbred line.

The Effect of Temperature and Photoperiod on Diapause Induction in Pupae of Scrobipalpa ocellatella (Lepidoptera: Gelechiidae).

Scrobipalpa ocellatella (Boyd) (Lepidoptera: Gelechiidae) is one of the most important pests of sugar beet that causes quantitative and qualitative yield loss in the late summer. To locate the position for diapause induction, combinations of constant temperatures at 15, 18, 20, and 25°C and day lengths of 8, 10, 12, 14, 16, and 24 h were studied from egg to adult emergence. The incidence of diapause peaked at 15 and 18°C, with the day lengths of 12 and 11 h, whereas low temperatures did not improve the effects of short photoperiods (day lengths of 8 and 10 h) in diapause induction. The results showed that the critical day length for diapause induction was 12.8 h at overall 15 and 18°C. It was observed that the third instar larvae were the most sensitive stage to the inductive photoperiod (12:12 [L:D] h). The non-24-h light-dark experiment showed that the nigh length is more important than the day lengths measurement. In a set of 24-h light-dark cycles at 2:12 (L:D) h, a 1-h light pulse declined diapause induction markedly 1 h after scotophase. Field monitoring of the S. ocellatella for 2 yr (2015 and 2016) showed that the 50% of larvae enter winter pupal diapause in early September and this proportion increases in response to a decrease in the day lengths and temperature. From this study, it was concluded that low temperature acts in conjunction with short-day photoperiod in diapause induction of S. ocellatella.

Screening for Resistance Against the Sugarbeet Root Maggot, Tetanops myopaeformis (Diptera: Ulidiidae), Using a Greenhouse Bioassay.

The sugarbeet root maggot, Tetanops myopaeformis (von Röder) (Diptera: Ulidiidae), is a major pest of sugar beet Beta vulgaris L. (Carophyllales: Amaranthaceae)in the United States and Canada. Larval feeding on roots can reduce both stand and yield. Current management practices are heavily reliant on chemical control. However, the carbamate and organophosphate insecticides that are commonly used against T. myopaeformis are being phased out of use. Host plant resistance against this pest shows promise, but difficulties with maintaining T. myopaeformis in culture have largely limited such studies to the field. A primary objective of this study was to develop protocols for rearing a laboratory colony of T. myopaeformis that would expedite assays aimed at screening for host plant resistance. Third (final) instar larvae were collected from the field and reared to the adult stage. These laboratory-reared adults laid eggs and ultimately produced a second generation of third-instar larvae in the lab. Adult flies reared from field-collected larvae were used to examine the modality of resistance of a known resistant variety by performing no-choice and paired-choice experiments alongside a susceptible variety in the greenhouse. Paired-choice tests showed no difference in oviposition rates between the two varieties, whereas no-choice tests showed significantly greater feeding damage and abundance of larvae on the susceptible variety. For the resistant variety examined here, we observed evidence of antibiosis, not antixenosis, as the putative modality of resistance. Our laboratory and greenhouse protocols can be used to expedite the process of developing varieties with resistance to this key pest of sugar beet.