Agricultural Greenhouses in São Tomé and Príncipe

Since 2016, STP has been funding the implementation of greenhouses, viewed as a viable way to guarantee, increase, and diversify production; supply the market; improve farmers' incomes; and mitigate climate change impacts. The greenhouses in selected districts were based on farmers' experiences in horticultural production, available agricultural area, and capacity of rural communities to organize themselves into small farmers' cooperatives. There are also private greenhouse initiatives. This chapter analyzed the current situation of the STP greenhouse project and its socioeconomic contribution to rural communities, proposing actions for its improvement, addressing climate changes and poverty reduction. Despite several weaknesses, mainly linked to lack of knowledge and mastery of technology, greenhouse production represents a viable alternative for horticulture development. Greenhouses, properly exploited, are a mechanism to mitigate climate change effects and ensure an increase in income and consequently reduce poverty and improve individual and collective living conditions.

Evaluating the Growth-promoting Effects of Microbial Biostimulants on Greenhouse Floriculture Crops

Microbial biostimulants can promote ornamental plant growth during production and improve crop performance under abiotic stresses. Even though biostimulants have shown potential in many agricultural applications, the effectiveness and specificity of many products are not well understood. The objective of this study was to analyze the growth-promoting effects of microbial biostimulants during the greenhouse production of floriculture crops. We evaluated 13 biostimulant products in greenhouse-grown zinnia (Zinnia elegans ‘Magellan Ivory’) and petunia (Petunia ×hybrida ‘Carpet White’) at low fertility (one-third of the optimal fertilizer concentration). Biostimulant products 1 and 2 containing multiple species of beneficial bacteria and fungi, and product 10 containing Bacillus subtilis QST 713, were found to increase various aspects of plant growth, including the growth index, leaf chlorophyll content (SPAD index), and shoot biomass. Both flower biomass and numbers were greater in petunia treated with product 1, and leaf size increased in zinnia treated with products 1, 2, and 10. Plants treated with these effective biostimulants at low fertility had similar or better growth and quality than untreated plants grown under optimal fertility. The concentration of various nutrient elements in leaves was higher in zinnia plants treated with biostimulant products 1, 2, or 10 compared with the negative control. Some putative mechanisms for biostimulant effectiveness, the possible reasons for biostimulant ineffectiveness, and the potential for using biostimulants as a sustainable cultural strategy are discussed. This study provides useful information about microbial biostimulant effectiveness, which is important for the development and utilization of biostimulants in the greenhouse production of floriculture plants.

Bradysia aff. impatiens and Bradysia aff. ocellaris in the semi-hydroponic strawberry production system in Southern Brazil

ABSTRACT: Soilless cultivation of strawberry is in expansion in Brazil due to factors like the reduction of phytosanitary problems and the possibility of extending the crop period, as well as the ergonometric facility for management of the culture. However, black fungus gnats (Sciaridae, Diptera) are ubiquitous pests in the greenhouse production system, causing direct and indirect damage to plants. ThIS study evaluated the occurrence of black fungus gnats species in semi-hydroponic cultivation of strawberry and to identify the species, as well as to describe the symptoms in infested plants. The research was developed in commercial productions of strawberry, in five municipalities (Arroio do Padre, Canguçu, Capão do Leão, Pelotas and Turuçu) during July to December 2017, where adult samples were collected twice a month, with petri dish traps containing water and neutral detergent placed inside the greenhouses between the plants. A total of 2030 adult gnats belonging to two species were collected. Bradysia aff. impatiens, accounted with 90.79% of the total, and Bradysia aff. ocellaris, accounted with 9.21%. In order to assist the correct determination of species, males of both species were identified and illustrated. With respect to the symptoms observed during the research, it was possible to verify since the wilted crown of plants to the death of plants, which were confirmed by the presence of larvae in the root system. As the occurrence of these insects is recent in strawberry, there is no pesticide registered in Brazil, so management strategies (cultural, physical, and sanitary) also are discussed.

The first report of Tomato brown rugose fruit virus in tomato in Norway

In May 2021, tomato (Solanum lycopersicum L.) plants with necrosis and ringspot symptoms were observed in a farm greenhouse at Sundbyfoss, Norway. This greenhouse production focused on ecological growing of several tomato varieties (i.e., “Blush Tiger”, “Sailor’s Luck”, “Evil Oliver”, etc.) with compost for local customers. The presence of tomato brown rugose fruit virus (ToBRFV) was suspected due to the symptoms in the diseased plants. Sap inoculation was carried out with extracts from 100 mg symptomatic tomato fresh leaves in 0.03 M PBS (phosphate buffered saline, pH 7.0), and inoculation on three Nicotiana tabacum cv. Xanthi plants at the 4-6 leaf stage grown in an experimental greenhouse. The test plants showed local necrotic lesions after 3-5 days. Two symptomatic leaf samples, one from tomato and the other from a test plant, were analysed by transmission electron microscope (TEM) with the help of negative staining. The samples were treated with 0.1 M PBS (pH 7.3) first and placed on carbon-coated EM grids and stained with 2% uranyl acetate before TEM observation. Rigid rod-shaped viral particles, typical of tobamovirus particls (around 300 nm) were observed. Total RNA was isolated from two tomato leaves showing symptoms using a Norgen Plant/Fungi RNA kit (Norgen Biotek, Canada). One-step reverse-transcription (RT)-PCR with specific primers ToBRFV-F/ToBRFV-R for ToBRFV (Alkowni et al. 2019), which amplified a 560-bp fragment, was performed. The sequence obtained by Sanger sequencing from the amplicon (535 nt) showed 99.8% nt identity with ToBRFV isolate PV-1241 (NCBI accession no. MZ202349) from DSMZ (Leibniz Institute, German) and was deposited in the GenBank database under the accession number OK358628. The infection was also confirmed with duplex real-time RT-PCR test for ToBRFV using CaTa28 and CSP1325 primers and probe (ISF 2020; EPPO, PM7/146 2021). In addition, eight tomato samples from the same farm greenhouse were collected according to cultivars, location in the greenhouse and symptoms before eradication and disinfection: four of the tomato samples were confirmed positive for ToBRFV with one-step RT-PCR as described above. A surveillance program for ToBRFV in commercial greenhouse production has been carried out in 2021 in Norway. Around 4000 tomato plants from 18 commercial tomato growers were tested. No positive ToBRFV samples have been detected. However, unregulated tomato seeds from abroad and self-propagation of tomato by private gardeners and hobby growers is a potential threat to commercial production of tomato in Norway. To our knowledge, this is the first report of ToBRFV associated with tomato in Norway and in the Nordic countries.

Environmental Amelioration Through Nutrient Calibration: Maximizing Carbon Sequestration in Hydroponic Greenhouse Production of Lactuca Sativa in Lahore’s Spring

This study explores the applicability of internationally prescribed nutrient recipes to greenhouse hydroponic production in Lahore. Lactuca sativa was hydroponically grown at different nutrient concentrations to uncover optimum nutrition for maximum foliage cover. Conclusions were based on visual analysis of foliage cover, as laboratory analysis of trial plants was beyond the scope of this environmental study. Nutrient levels that displayed the best foliage cover in Lahore-based greenhouse during spring weather were different from concentrations kept in US- or Europe-based hydroponic greenhouses. Plant trials conducted for this article explain the adjustments that must be made to hydroponic recipes discussed in international literature; if they are to be used in polyhouse hydroponic production in Lahore’s warmer climate.

Production Costs and Profitability for Selected Greenhouse Grown Annual Bedding Plants: Partial Enterprise Budgeting and Sensitivity Analysis

The objective of the research described in this publication was to estimate the cost of greenhouse production for selected annual bedding plants and help growers to determine how the particular crop they are growing influences profitability.

Economic Analysis of Medical Cannabis Greenhouse Production for Cbd in Greece

A field experiment was conducted in the Agricultural University of Athens in order to evaluate the effect of different greenhouse cover materials on the CBD yield. Cannabis (Cannabis sativa L var. Futura 75) plants were grown in three different greenhouses, each constructed with different polyethylene films by PLASTIKA KRITIS S.A. The overall CBD yield per greenhouse was estimated once the cannabis buds matured. Following this evaluation, a business plan was formed for the greenhouse whose cover materials prompted the highest CBD yield. Out of the three greenhouses (GH1, GH2, and GH3), the highest CBD yield was reported on GH2. Two different cover materials, with different properties, were used for the construction of GH2, EVO 7507 AC and EVO 7526 AC. The results indicate that in a five-year span, cannabis production in greenhouses built with the aforementioned materials, could result in a Net Profit of more than 25.000.000 € ha-1. In conclusion, greenhouse cover materials should always be considered in cannabis greenhouse production. Even though greenhouse cannabis production for CBD oil seems to be a potentially profitable business in Greece, selecting appropriate cover materials can significantly increase producer’s profit.