scholarly journals Efficacy of Beauveria bassiana against the cotton leaf roller, Haritalodes (Syllepte) derogata (Fabricius, 1775) (Lepidoptera: Crambidae) under laboratory conditions.

2021 ◽  
Vol 157 ◽  
pp. 16254-16266
Author(s):  
Dannon H. Fabrice ◽  
Douro Kpindou O. Kobi ◽  
Toffa Mehinto Joelle ◽  
Zantchedji D. M. Désiré ◽  
Zinsou A. Valerien ◽  
...  

Objective: The leaf-roller caterpillar Haritalodes (=Syllepte) derogata (Fabricius, 1775) (Lepidoptera: Crambidae) induces high yield losses by damaging cotton leaves and reducing the photosynthetic activity of the plant. Laboratory bioassays were carried to evaluate the effect of Beauveria bassiana on the survival of H. derogata larvae. Methodology and results: In the first trial, screening of thirteen B. bassiana isolates was performed on third larval instars at 107 conidia.mL-1 . In the second trial, effects of five concentrations (105 to 109 conidia.mL-1 ) of the three best isolates of the fungus were tested. Conidia suspension was applied on each larva topically. Germination rates of conidia used varied between 90.2% to 95.7%, 24 hours after incubation. Five isolates were found to be the most promising namely Bb116, Bb3, Bb11, Bb6 and Bb115. In the second bioassay, caterpillar mortality increased with fungal concentration. Lethal Concentration (LC50) was estimated to 1.18x1015 conidia.mL-1 , 1.75x1013 conidia.mL-1 , 1.75x1013 conidia.mL-1 , 9 days after inoculation for Bb3, Bb11 and Bb115, respectively. Conclusion and application of results: The use of B. bassiana as a biopesticide against H. derogata could be a good alternative method to control the pest. It is an environmentally friendly method with less side effects compared to the application of synthetic pesticides on cotton. This method could be tested in future station and field experiments. Keywords: Cotton, Integrated pest management, Haritalodes (=Syllepte) derogata, Beauveria bassiana, Lethal Concentration.

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1054
Author(s):  
Bo Li ◽  
Xinyu Chen ◽  
Xiaoxu Shi ◽  
Jian Liu ◽  
Yafeng Wei ◽  
...  

Ridge tillage is an effective agronomic practice and a miniature precision agriculture; however, its effects on the growth of faba beans (Vicia faba L.) are poorly understood. This study aimed to determine the effect of ridge tillage and straw mulching on the root growth, nutrient accumulation and yield of faba beans. Field experiments were conducted during 2016 and 2017 cropping seasons and comprised four treatments: ridge tillage without any mulching (RT), flat tillage without any mulch (FT), flat tillage with rice straw mulched on the ridge tillage (FTRSM) and ridge tillage with rice straw mulched on the ridge tillage (RTRSM). The RT and RTRSM increased soil temperature and decreased soil humidity and improved soil total nitrogen, total phosphorus, available potassium and organic matter. RT and RTRSM increased the root length density, root surface area, root diameter and root activity of faba beans at flowering and harvest periods. The RT and RTRSM also increased the nitrogen, phosphorus, potassium absorption and the yield of faba beans. These results indicated that ridge tillage and straw mulching affect faba bean growth by improving soil moisture conditions and providing good air permeability and effective soil nutrition supply. This study provides a theoretical basis for the high yield cultivation improvement of faba beans.


Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 691
Author(s):  
Omotuyole Isiaka Ambali ◽  
Francisco Jose Areal ◽  
Nikolaos Georgantzis

This study analyses farmers’ adoption of improved rice technology, taking into account farmers’ risk preferences; the unobserved spatial heterogeneity associated with farmers’ risk preferences; farmers’ household and farm characteristics; farm locations, farmers’ access to information, and their perceptions on the rice improved varieties (i.e., high yield varieties, HYV). The study used data obtained from field experiments and a survey conducted in 2016 in Nigeria. An instrumental-variable probit model was estimated to account for potential endogenous farmers’ risk preference in the adoption decision model. Results show that risk averse (risk avoidant) farmers are less likely to adopt HYV, with the spatial lags of farmers’ risk attitudes found to be a good instrument for spatially unobserved variables (e.g., environmental and climatic factors). We conclude that studies supporting policy action aiming at the diffusion of improved rice varieties need to collect information, if possible, on farmers’ risk attitudes, local environmental and climatic conditions (e.g., climatic, topographic, soil quality, pest incidence) in order to ease the design and evaluation of policy actions on the adoption of improved agricultural technology.


2021 ◽  
pp. 34-37
Author(s):  
В.К. Сердеров ◽  
Д.В. Сердерова

Большое значение в увеличении продуктивности картофеля имеет внедрение в производство перспективных высокоурожайных сортов и гибридов, приспособленных к местным природно-климатическим условиям возделывания, от чего зависят эффективность отрасли и себестоимость продукции. Цель работы – изучить влияние климатических условий на продуктивность и качественные показатели сортов и гибридов картофеля, а также использование ими благоприятных почвенно-климатических условий высокогорья Республики Дагестан, для размножения и внедрения в производство новых перспективных, высокоурожайных, приспособленных к условиям среды выращивания сортов картофеля с комплексом хозяйственно-ценных признаков. Объектом изучения послужили сорта картофеля раннего, среднераннего и среднего сроков созревания российской, белорусской и иностранной селекции. Полевые опыты закладывали в 2014–2017 годах на высоте 2000–2200 м, на землях горного опорного пункта «Курахский» Курахского района и на равнинной провинции (Прикаспийской низменности) на территории дачного массива «Наука» Махачкалинского района Республики Дагестан. Схема посадки – 70×30 см, повторность – четырехкратная. Технология выращивания картофеля – гребневая. При проведении полевых опытов использовали общепринятые методики. Практически все сорта картофеля, выращенные на равнинной провинции, сформировали высокий урожай в первый год и при дальнейшем размножении в результате развития вирусных болезней резко снизили свои продуктивные качества. Наиболее высокая урожайность в среднем за три года отмечена у сортов Жуковский ранний (20,8 т/га), Импала (20,5 т/га), Невский (17,8 т/га), Предгорный (16,9 т/га) и Удача (16,3 т/га). В свою очередь, горная провинция Дагестана характеризовалась благоприятными почвенно-климатическими условиями для возделывания как продовольственного картофеля, так и для организации первичного семеноводства на безвирусной основе и размножения перспективных сортов этой культуры. В среднем за годы исследований в горной провинции по урожайности выделились сорта Сильвана (37,4 т/га), Удача (37,6 т/га), Рокко (33,3 т/га), Импала (31,7 т/га), Жуковский ранний (29,0 т/га), Предгорный (27,7 т/га) и Примобелла (27,7 т/га), а также гибриды № 12.40/17 (43,1 т/га) и № 13.61/61 (38,8 т/га). The introduction of promising high-yielding varieties and hybrids adapted to the local natural and climatic conditions of cultivation is of great importance in increasing the productivity of potatoes, which determines the efficiency of the industry and the cost of production. The aim of the work is to study the influence of climatic conditions on the productivity and quality indicators of potato varieties and hybrids, as well as their use of favorable soil and climatic conditions in the highlands of the Republic of Dagestan, for breeding and introducing into production new promising, high-yielding, adapted to the growing environment of potato varieties with a complex of economically valuable characteristics. The object of the study was potato varieties of early, mid-early and medium maturation periods of Russian, Belarusian and foreign selection. Field experiments were conducted in 2014–2017 at an altitude of 2000–2200 m, on the lands of the mountain stronghold Kurakhsky of the Kukhar district and on the plain province (the Caspian lowland) on the territory of the suburban area Nauka of the Makhachkala district of the Republic of Dagestan. The landing scheme is 70×30 cm, the repeatability is four times. The technology of growing potatoes is combed. When conducting field experiments, generally accepted methods were used. Almost all potato varieties grown in the lowland province formed a high yield in the first year and, with further propagation, as a result of the development of viral diseases, sharply reduced their productive qualities. The highest yield on average for three years was observed in the varieties Zhukovskiy ranniy (20.8 t/ha), Impala (20.5 t/ha), Nevsky (17.8 t/ha), Predgornyy (16.9 t/ha) and Udacha (16.3 t/ha). In turn, the mountain province of Dagestan was characterized by favorable soil and climatic conditions for the cultivation of both food potatoes, and for the organization of primary seed production on a virus-free basis and the reproduction of promising varieties of this crop. On average, over the years of research in the mountain province, the varieties Silvana (37.4 t/ha), Udacha (37.6 t/ha), Rocco (33.3 t/ha), Impala (31.7 t/ha), Zhukovskiy ranniy (29.0 t/ha), Predgornyy (27.7 t/ha) and Primobella (27.7 t/ha), as well as hybrids No.12.40/17 (43.1 t/ha) and No.13.61/61 (38.8 t/ha) were distinguished by yield.


2008 ◽  
Vol 2 (1) ◽  
pp. 24-32
Author(s):  
Sh. H. AL-Obaidi ◽  
L. K. AL-Ani ◽  
W. A. Hussain

A field study were conducted to evaluate the efficacy of the entomopathogenic fungi Beauveria bassiana as abiocontrol agent for the cotton leaf worm Spodoptera littoralis infesting potato plants. Results indicated that soil treatment of the entomopathogenic fungi significantly reduced the percentage of plant infestation to 64.3, 60.7 % after 14, 21 days. Results of the infection intensity also significantly reduced in treatment of entomopathogenic fungi in soil to 18.7, 9.9 pore/leaf after 14, 21 days of treatment.The results revealed the higher efficiency of entomopathogenic fungi on plant yield, it become 633.3 gm in entomopathogenic fungi in soil treatment.


2019 ◽  
Vol 18 (3) ◽  
Author(s):  
I Nyoman Pugeg Aryantha ◽  
Wahyu Setyaji Dwiantara

Beauveria bassiana produces several metabolites that are toxic to insects so that it can be used as a biological insect control agent as an alternative to synthetic pesticides. The aim of this study was to determine the larvicidal activity of ethyl acetate and hexane extract from B. bassiana filtrate culture against Aedes aegypti 2nd instar larvae. This research was it cooked by determining the optimum age of spore inoculum of B. bassiana on the Potato Dextrose Agar (PDA) based on the number of spores and its viability. Afterwards, we determine the incubation time of B. bassiana in the Potato Dextrose Broth (PDB) in order to obtain filtrate culture which have highest mortality effects against Ae. aegypti 2nd instar larvae. B. bassiana filtrate culture was extracted with hexane and ethyl acetate and tested aegypti for larvicidal activity with a concentration range of 50, 100, 200, 300 ppm. The LC50 value was carried out by probit analysis. The results showed that ninth day old culture in the PDA was the optimum age of spore inoculum with the spore number and viability were 2.54 x 107 spore/mL and 93.46% respectively. The filtrate of sixth day old culture in PDB medium gave 100% mortality against 2nd instar Ae. Aegypti larvae. LC50 values of ethyl acetate and hexane extract were 117.28 dan 287.09 ppm. These results showed that the ethyl acetate and hexane extract of B. bassiana filtrate culture have biopesticide potential against 2nd instar Ae. aegypti larvae.   


2015 ◽  
Vol 27 (4) ◽  
pp. 2833-2834 ◽  
Author(s):  
Jing Zhao ◽  
Yang Sun ◽  
Liubin Xiao ◽  
Yongan Tan ◽  
Lixin Bai

Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 106 ◽  
Author(s):  
Ke Zhang ◽  
Xiaojun Liu ◽  
Syed Tahir Ata-Ul-Karim ◽  
Jingshan Lu ◽  
Brian Krienke ◽  
...  

Accurate estimation of the nitrogen (N) spatial distribution of rice (Oryza sativa L.) is imperative when it is sought to maintain regional and global carbon balances. We systematically evaluated the normalized differences of the soil and plant analysis development (SPAD) index (the normalized difference SPAD indexes, NDSIs) between the upper (the first and second leaves from the top), and lower (the third and fourth leaves from the top) leaves of Japonica rice. Four multi-location, multi-N rate (0–390 kg ha−1) field experiments were conducted using seven Japonica rice cultivars (9915, 27123, Wuxiangjing14, Wunyunjing19, Wunyunjing24, Liangyou9, and Yongyou8). Growth analyses were performed at different growth stages ranging from tillering (TI) to the ripening period (RP). We measured leaf N concentration (LNC), the N nutrition index (NNI), the NDSI, and rice grain yield at maturity. The relationships among the NDSI, LNC, and NNI at different growth stages showed that the NDSI values of the third and fourth fully expanded leaves more reliably reflected the N nutritional status than those of the first and second fully expanded leaves (LNC: NDSIL3,4, R2 > 0.81; NDSIothers, 0.77 > R2 > 0.06; NNI: NDSIL3,4, R2 > 0.83; NDSIothers, 0.76 > R2 > 0.07; all p < 0.01). Two new diagnostic models based on the NDSIL3,4 (from the tillering to the ripening period) can be used for effective diagnosis of the LNC and NNI, which exhibited reasonable distributions of residuals (LNC: relative root mean square error (RRMSE) = 0.0683; NNI: RRMSE = 0.0688; p < 0.01). The relationship between grain yield, predicted yield, and NDSIL3,4 were established during critical growth stages (from the stem elongation to the heading stages; R2 = 0.53, p < 0.01, RRMSE = 0.106). An NDSIL3,4 high-yield change curve was drawn to describe critical NDSIL3,4 values for a high-yield target (10.28 t ha−1). Furthermore, dynamic-critical curve models based on the NDSIL3,4 allowed a precise description of rice N status, facilitating the timing of fertilization decisions to optimize yields in the intensive rice cropping systems of eastern China.


2020 ◽  
Vol 133 (12) ◽  
pp. 3287-3297
Author(s):  
Tianzi Lin ◽  
Cong Zhou ◽  
Gaoming Chen ◽  
Jun Yu ◽  
Wei Wu ◽  
...  

Abstract Key message Heterosis QTLs, including qSS7 and qHD8, with dominance effects were identified through GBS and large-scale phenotyping of CSSLs and hybrid F1 populations in a paddy field. Abstract Heterosis has contributed immensely to agricultural production, but its genetic basis is unclear. We evaluated dominance effects by creating two hybrid populations: a B-homo set with a homozygous background and heterozygous chromosomal segments and a B-heter set with a heterozygous background and homozygous segments. This was achieved by crossing a set of 156 backcrossed-derived chromosome segment substitution lines (CSSLs) with their recurrent parent (9311), the male parent of the first super-high-yield hybrid Liangyoupei9 (LYP9), and with the female parent (PA64s) of the hybrid. The CSSLs were subjected to a genotyping-by-sequencing analysis to develop a genetic map of segments introduced from the PA64s. We evaluated the heterotic effects on eight yield-related traits in the hybrid variety and F1 populations in large-scale field experiments over 2 years. Using a linkage map consisting of high-density SNPs, we identified heterosis-associated genes in LYP9. Five candidate genes contributed to the high yield of LYP9, with qSS7 and qHD8 repeatedly detected in both B-hybrid populations. The heterozygous segments harboring qSS7 and qHD8 showed dominance effects that contributed to the heterosis of yield components in the hybrid rice variety Liangyoupei9.


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