Methoprene, a juvenile hormone analogue, modifies maturation and emergence in overwintering Osmia rufa L. adults

The development of methods aimed at activation of imagos at any point of wintering provides a compelling potential avenue to utilize bees for pollination of greenhouse crops during autumn, winter, and early spring. In this study, we tested methoprene, a juvenile hormone (JH) analogue as a chemical stimulant to end a diapause of Osmia rufa L. and enable bee activation and emergence under experimental conditions. The application of methoprene significantly reduced the emergence time of adult bees in winter months as compared to vehicle (acetone) and negative controls. Bees treated with methoprene started to emerge 3–6 days earlier than bees from acetone and control groups and finished emergence 2–6 days earlier too. Statistically significant differences were observed between methoprene and controls groups of male and female in all tested incubation periods. It was also observed that the effects of methoprene were significantly more effective in female specimens during the first 2 months of winter. Moreover, in females, methoprene improved reproductive traits such as an increase in the size of terminal oocytes. Similarly, in males, methoprene treatment resulted in a significant increase in a seminal vesicle size and dynamic elevation of spermatozoa number. Taken together, our results indicate that methoprene may play an important role in the termination of diapause, bee activation, and emergence.

Valuation growing cocktail-type cucumber hybrids in a vertical farm

На сегодняшний день главные искусственные источники освещения растений – натриевые лампы высокого давления. Однако в 2021 году уже во многих тепличных комбинатах РФ и других стран мира активно используют светодиодные лампы с различными спектральными режимами в основном в качестве досвечивания. Анализ научных работ показал, что практически отсутствуют достоверные данные по выращиванию основных тепличных культур в условиях использования только светодиодов без естественного освещения. Это не дает полной объективной картины эффективности использования светодиодных ламп. Цель исследований: определить эффективность применения светодиодных ламп при выращивании коктейльных гибридов огурца при повышенной густоте посадки в условиях вертикальной фермы. Исследования проводили в летне-осеннем и весенне-летнем оборотах в 2020–2021 годах на территории УНПЦ «Овощная опытная станция имени В.И. Эдельштейна» РГАУ – МСХА имени К.А. Тимирязева в стеклянных теплицах без досвечивания и ООО «Вертикальные фермы» в закрытом помещении без доступа солнечного света (Москва). Объект исследования – гибриды огурца F1 Ларино, F1 Кватрино, F1 Квирк. В теплице выращивали огурец по малообъемной технологии, в качестве субстрата использовали верховой торф. Для облучения растений применяли светодиодные модули производства ООО «Вертикальные фермы» (30 Вт, 50×7,2 см, в рабочем режиме 2,8–2,9 мкМоль/Дж), которые располагались на расстоянии 0,4 м от растений. Облучали растения по 16 часов в сутки. Установлено, что выращивание растений огурца в вертикальных фермах с использованием полноспектральных светодиодных облучателей и густоты посадки 11,4 раст/м2способствует увеличению общей урожайности огурца в сравнении с остекленной теплицей. При выращивании огурца в условиях вертикальной фермы в плодах огурца накапливалось меньшее количество нитратов (102–105 мг/кг), отмечено более высокое количество содержания сахаров (1,90–1,98%) и сухого вещества (6,21–6,28%) по сравнению с плодами, полученными при выращивании в теплице. Перспективно дальнейшее изучение выращивания культуры огурца в вертикальных фермах с использованием светодиодов. Today, the main artificial sources of plant illumination are high pressure sodium lamps. However, in 2021, many greenhouse plants of the Russian Federation and other countries of the world are actively using LED lamps with various spectral modes mainly as additional illumination. The analysis of scientific papers has shown that there is practically no reliable data on the cultivation of the main greenhouse crops in conditions of using only LEDs without natural lighting. This does not give a complete objective picture of the efficiency of using LED lamps. The purpose of the research: to determine the effectiveness of the use of LED lamps in the cultivation of cucumber cocktail hybrids with increased planting density in a vertical farm. The research was carried out in summer-autumn and spring-summer turns in 2020–2021 on the territory of the V.I. Edelstein Vegetable Experimental Station of the K.A. Timiryazev Russian State Agricultural Academy in glass greenhouses without additional illumination and Vertical Farms LLC indoors without access to sunlight (Moscow). The object of research: cucumber hybrids F1 Larino, F1 Kvatrino, F1Kvirk. Cucumber was grown in the greenhouse using low-volume technology, riding peat was used as a substrate. For irradiation of plants, LED modules manufactured by Vertical Farms LLC (30 W, 50×7.2 cm, in operating mode 2.8–2.9 mmol/J) were used, which were located at a distance of 0.4 m from the plants. Plants were irradiated for 16 hours a day. It was found that the cultivation of cucumber plants in vertical farms using full-spectrum LED irradiators and a planting density of 11.4 rast/m2 contributes to an increase in the total yield of cucumber in comparison with a glazed greenhouse. When growing cucumbers in a vertical farm, fewer nitrates (102–105 mg/kg) accumulated in cucumber fruits, a higher amount of sugar content (1.90–1.98%) and dry matter (6.21–6.28%) were noted compared to fruits obtained when grown in a greenhouse. It is promising to further study the cultivation of cucumber culture in vertical farms using LEDs.

Energy and Water Related Parameters in Tomato and Cucumber Greenhouse Crops in Semiarid Mediterranean Regions. A Review, Part II: Irrigation and Fertigation

Increasing agricultural systems’ resource efficiency is the key action for producing adequate food quantities in semi-arid Mediterranean regions while coping with water scarcity, environmental constraints and economic issues. Optimisation of irrigation and fertigation practices imposes different approaches, considering plant-water-soil relationships based on prevailing greenhouse microclimatic conditions, ensuring optimal production per drop of water and unit of fertiliser. In the content of "precision agricultural farming systems", nutrient uptake modelling, phyto-sensing, smart and sustainable technologies must be applied for monitoring and evaluating water and nutrients crops supply. However, in many cases, the use of irrigation and fertigation recipes given in the literature may not be compatible in the Mediterranean, as they usually originated based on northern European climatic conditions. The objective of this work is an attempt to understand various aspects of irrigation and fertigation management in vegetable fruiting crops such as tomato and cucumber towards nutrients and water resource sustainability in Mediterranean greenhouses.

Lethal and sublethal effects of bifenazate on the biological parameters of Tetranychus truncatus Ehara (Acari: Tetranychidae)

Tetranychus truncatus Ehara (Acari: Tetranychidae) is one of the serious pests that infests different agricultural crops in field and greenhouse crops, and its distribution is limited to mostly Asian countries. The experiments were conducted to know the effectiveness of different concentrations of bifenazate against the T. truncatus, and to evaluate and compare the demographic parameters of T. truncatus on host plant Lablab purpureus (L.) Sweet (Fabaceae), which were obtained from females treated with bifenazate. The LC15, LC30, LC50 and LC90 values are determined through the bioassay from the results of the first application of bifenazate on adult females of T. truncatus. The LC15, LC30, LC50 and LC90 concentrations of bifenazate were 0.417, 1.028, 2.591 and 24.792 ml/l, respectively. The response of adult females against the two lethal concentrations (LC15 and LC30) was mostly alike but had a little bit difference. The differences in life table parameters were observed between control and treated spider mites. The results demonstrated that LC15 and LC30 of bifenazate could reduce the survival rate, oviposition period, fecundity and longevity of females of T. truncatus and it significantly affected the developmental times, especially larval duration and fecundity of T. truncatus. Life-table parameters of T. truncatus were much reduced in LC15 and LC30 compared to the control and their growth and other factors showed significant differences. The present study showed that the lower lethal concentration (LC15 and LC30) of the tested acaricide showed negative effects on survivorship and life-table parameters of the subsequent generation of T. truncatus.

Monitoring of Agricultural Conditions in Greenhouse Crops Using Edge Computing and IoT.

This work presents an Internet of Things (IoT) system and edge computing for monitoring crop conditions by developing a system to collect information on parameters related to the crop weather conditions, this data is recollected with edge computing system. The data is sent to the server for processing, then forwarded to the user via the IoT protocols and procedures. The purpose is to collect data in real time for analysis and allow decision-making by the system and the farmer. The user can interact with the system remotely and receive the specified alerts and conditions. The initial results show that the system provides complete information on the status of the parameters, enabling management of greenhouse crops.

Computational Fluid Dynamics Modelling of the Microclimate within the Boundary Layer of Leaves Leading to Improved Pest Control Management and Low-Input Greenhouse

This work aims at using the Computational Fluid Dynamic (CFD) approach to study the distributed microclimate in the leaf boundary layer of greenhouse crops. Understanding the interactions in this microclimate of this natural habitat of plant pests (i.e., boundary layer of leaves), is a prerequisite for their control through targeted climate management for sustainable greenhouse production. The temperature and humidity simulations, inside the greenhouse, were performed using CFD code which has been adapted to simulate the plant activity within each mesh in the crop canopy. The air temperature and air humidity profiles within the boundary layer of leaves were deduced from the local surrounding climate parameters, based on an analytical approach, encapsulated in a Used Defined Function (UDF), and dynamically linked to the CFD solver, a work that forms an innovative and original task. Thus, this model represents a new approach to investigate the microclimate in the boundary layer of leaves under greenhouses, which resolves the issue of the inaccessibility of this area by the conventionnel measurement tools. The findings clearly showed that (i) contrarily to what might be expected, the microclimate parameters within the boundary layer of leaves are different from the surrounding climate in the greenhouse. This is particularly visible during photoperiods when the plant’s transpiration activity is at its maximum and that (ii) the climatic parameters in the leaf boundary layer are more coupled with leaf surfaces than with those of greenhouse air. These results can help developing localized intervention strategies on the microclimate within boundary layer of plant leaves, leading to improved and sustainable pest control management. The developed climatic strategies will make it possible to optimize resources use efficiency.

Host-virus and virus-virus interactions in broad host range alphabaculoviruses: implications for the development of virus-based insecticides

This thesis examined the insecticidal potential of the broad host range baculovirus Mamestra brassicae multiple nucleopolyhedrovirus (MbMNPV), and this interaction with Helicoverpa armigera multiple nucleopolyhedrovirus (HaMNPV) during the coinfection of a shared host. The results provide greater understanding of host-virus and virus-virus interactions in broad host range alphabaculoviruses that should help define effective strategies for pest control in field and greenhouse crops. First, the insecticidal activity and stability of the two closely related alphabaculovirus isolates, HearMNPV and MbMNPV derived from the commercial bioinsecticide Mamestrin®, were evaluated in a permissive (Spodoptera exigua) and a semi-permissive host (Spodoptera littoralis). The genetic structure of MbMNPV derived from the biological insecticideMamestrin® was then studied with the aim of assessing the insecticide properties of the genotypic variants comprised this wild-type isolate. Finally, interactions between two phylogenetically closely related viruses during coinfection of a shared host were analysed. In conclusion, the results obtained in this thesis contribute to a better understanding of the interactions between viruses and their hosts, which can contribute to the development of baculovirus-based insecticides and to design of effective strategies for the control of lepidopteran pest complexes.

Intraguild Interactions between the Mealybug Predators Cryptolaemus montrouzieri and Chrysoperla carnea

The ladybird Cryptolaemus montrouzieri and the green lacewing Chrysoperla carnea have shown potential for use in augmentative biological control of mealybug pests in greenhouse crops. In the context of combining these predators within an integrated pest management system, the risk of negative intraguild interactions between both predators was evaluated in a laboratory setting. Different life stages of either predator were confronted in petri dish arenas containing a Ficus benjamina leaf, and after 24 h the incidence and direction of intraguild predation (IGP) was recorded for each combination. The effect of adding Planococcus citri nymphs or Ephestia kuehniella eggs as extraguild prey on the level of IGP was also studied. IGP was frequently observed between the two predator species and was asymmetrical in favour of C. carnea in most cases. The presence of extraguild prey reduced the number of IGP events between the predators to a similar extent. The relevance of the observed intraguild interactions for the combined use of these predators in protected cultivation is discussed.