HortResearch

Coccinella septempunctata (Linnaeus, 1758) is a voracious predator all over the world where aphids have found a niche. Behavioral studies of C. septempunctata are very important to make them effective bio-controllers. Therefore, this study explains the functional response of C. septempunctata praying on two distinct aphid species, examined in this work at two different temperatures. Six different prey densities (4, 8, 16, 32, 64, and 128 aphids) and two different temperatures (15 and 25 °C) were used in the experiment. All of the development stages of the predator were used to perform the experiment. Every experiment was replicated five times. The type and parameters of functional response were ascertained by the application of Roger’s random predator models and logistic regression. Results showed that C. septempunctata adults and larvae both had a type II functional reaction against the tested aphids in both temperatures. When comparing the fourth instar to other predatory stages, the attack rate against both aphids was shown to be greater. As the temperature rose, so did the attack rate. Fourth instar larvae exhibited attack rates of 1.314 h−1 on Aphis nerii Fonscolombe, 1758 (Hemiptera: Aphididae) and 1.959 h−1 on Lipaphis erysimi Kaltenbach, 1843 (Hemiptera: Aphididae) at 15 °C, while at 25 °C, the rates were 1.747 h−1 and 1.321 h−1, respectively. Handling time was influenced by both temperature and predator stage. As the temperature increased, the handling time of the later predatory stages decreased. This study suggests that later predatory stages of C. septempunctatas actively hunt aphids at higher temperatures.

The pursuit of sustainable and productive agriculture demands the exploration of innovative approaches to improve plant productivity and soil health. The utilization of natural agricultural biostimulants, such as extracts from seaweed, fish, and humus, has gained prominence as an ecological strategy to achieve this goal. In this study we investigated the effectiveness of a fortified biostimulant extract (FBE), composed of extracts from seaweed, fish, and humus, on tomato plant physiology, productivity, and growing media properties, and estimated carbon emissions associated with tomato production. The FBE was applied to the growing media of tomato plants produced in a greenhouse, in experiments over two growing seasons. The productivity assessments demonstrated that the application of FBE significantly increased tomato fruit yield by 20% and relative marketable fruit yield by 27%, and reduced estimated greenhouse gas (GHG) emissions associated with production by 29%. FBE treatment improved plant shoot and root biomass, accelerated flower and fruit set initiation, and increased chlorophyll content in leaves, resulting in enhanced plant physiology and advanced development. FBE treatment positively influenced the availability of crucial nutrients such as nitrogen, phosphorus, and iron in the growing media. FBE promoted the growth of total active microbes in the growing media, particularly the fungal population, which plays an important role in nutrient cycling and health. These findings highlight the beneficial effects of the FBE due to enhanced plant productivity and growth, improved fertility, the promotion of beneficial plant and growing media interactions, and the reduction in estimated GHG emissions.

Citrus canker (CC), caused by one of the most destructive subfamilies of the bacterial phytopathogen Xanthomonas citri subsp. Citri (Xcc), poses a serious threat to the significantly important citrus fruit crop grown worldwide. This has been the subject of ongoing epidemiological and disease management research. Currently, five different forms have been identified of CC, in which Canker A (Xanthomonas citri subsp. citri) being the most harmful and infecting the majority of citrus cultivars. Severe infection symptoms include leaf loss, premature fruit drop, dieback, severe fruit blemishing or discoloration, and a decrease in fruit quality. The infection spreads rapidly through wind, rain splash, and warm and humid climates. The study of the chromosomal and plasmid DNA of bacterium has revealed the evolutionary pattern among the pathovars, and research on the Xcc genome has advanced our understanding of how the bacteria specifically recognize and infect plants, spread within the host, and propagates itself. Quarantine or exclusion programs, which prohibit the introduction of infected citrus plant material into existing stock, are still in use. Other measures include eliminating sources of inoculum, using resistant hosts, applying copper spray for protection, and implementing windbreak systems. The main focus of this study is to highlight the most recent developments in the fields of Xcc pathogenesis, epidemiology, symptoms, detection and identification, host range, spread, susceptibility, and management. Additionally, it presents an analysis of the economic impact of this disease on the citrus industry and suggests strategies to reduce its spread, including the need for international collaboration and research to reduce the impact of this disease on the global citrus industry.

The excessive fruit load on various fruit trees is an obstacle in achieving sustainable production. Fruit thinning helps to improve fruit quality attributes by reducing crop load. Therefore, a field study was carried out to evaluate the impact of fruit thinning on pomegranate. The four levels of fruit thinning were applied that including without thinning of a cluster (control), keeping three fruits (T1), two fruits (T2) and one fruit per cluster (T3). The effect of fruit thinning on physical and biochemical quality attributes of three pomegranate cultivars (Sindhuri, Kalehar and Sava) were evaluated during two consecutive growing seasons (2018 and 2019). The results revealed that Sindhuri followed by Kalehar and Sava showed significant improvement in fruit weight, fruit length, fruit width, A-grade fruit percentage, arils weight percentage, hundred arils weight, juice contents and peel redness (a*) when applied T3 (one fruit per cluster) while plant yield, peel weight percentage, peel thickness, lightness (L), yellowness (b*), fruit firmness, percentage of B grade and C grade fruits were significantellyreduced. The value of total soluble solid (TSS), pH, ascorbic acid, anthocyanin, antioxidant activity (AA), superoxide dismutase (SOD) and catalase (CAT) was also improved in T3 while titratable acidity (TA), total phenolic contents (TPC) and polyphenol oxidase (PPO) were reduced significantly. These observations indicate that reducing crop load by thinning (one fruit per cluster) could be a viable strategy to improve fruit quality attributes in pomegranate fruit. Conclusively, one fruit per cluster (T3) significantly improved fruit's physical and biochemical attributes in pomegranate cultivars (Sindhuri, Kalehar and Sava).