Development of a Cassava Harvester

Cassava is a major source of food and raw material for domestic and industrial uses in Nigeria. Consequently, the technologies involved in its cultivation from planting to harvesting require proper development. This paper reports the development of a labour-saving technology for harvesting cassava using standard procedures for designing soil engaging implements. Locally available materials were also used in the fabrication of the harvester. Results of trial tests indicate a digging efficiency of 58.9%, fuel consumption of 16 l/ha, field capacity of 0.11 ha/hr, field efficiency of 67.9% and root damage of 43.03%. The total cost of fabricating the machine was 184,000 naira only. Further tests under various soil and operational conditions for improvement and optimization were recommended for the purpose of patenting for commercialization.

The Use of Fermented Typha Domingensis Residues by Pleurotus Ostreatus as A bio-Fortification to Control Root Disease on Cucumber Caused by Rhizoctonia Solani

Cucumber is one of important crops and susceptible to root disease caused by Rhizoctonia solani. The study aimed to evaluate the efficiency of two isolates of P. ostreatus (Ah and Ak) and soil treatment with several rates of Typha domingensis residues fermented by P. ostreatus to control R. solani that causes root diseases on cucumbers. In vitro trails, R. solani inhibited significantly by isolate (Ah) as well as redial mycelial growth and the percentage of cucumber seeds germination. In field trails, the number of germinated seedlings was highest at fermented T. domingensis 59.81 compare to control treatment which was 59.81. Disease severity (DS) of root damage was recorded in R. solani and R. solani + Fermented T. domingensis treatments and reached 70.4 and 64.27 respectively.

Physiological causes of transplantation shock on rice growth inhibition and delayed heading

Transplanting is an important rice cultivation method; however, transplanting shock commonly affects grain yield, and the mechanisms underlying the inhibition of growth, development, and delayed heading caused by transplanting shock have not yet been clearly elucidated. Here, we investigated the effects of seedling age, temperature, and root damage during transplanting on growth, development, and time to heading, both under artificially controlled and natural day length. Additionally, we investigated the impact of seedling root growth space and the potential mitigating effects of residual seed nutrients on young transplanted seedlings. The delay in heading in transplanted versus directly seeded plants was affected more by growth inhibition during the seedling period than by root damage during transplanting. However, root damage had an effect on the inhibition of leaf and tiller development, and the ratio of leaves to tillers increased because tiller development was inhibited more by transplanting shock compared with leaf development. Based on these findings, we propose factors reflecting the delay in growth due to transplanting shock that should be included for more accurate rice phenology modeling and suggest advantageous seeding conditions and transplanting methods for improved rice cultivation and yield in response to climate change.

Can the botanical azadirachtin replace phased-out soil insecticides in suppressing the soil insect pest Diabrotica virgifera virgifera?

Background Due to recent bans on the use of several soil insecticides and insecticidal seed coatings, soil-dwelling insect pests are increasingly difficult to manage. One example is the western corn rootworm (Diabrotica virgifera virgifera, Coleoptera: Chrysomelidae), a serious root-feeder of maize (Zea mays). We investigated whether the less problematic botanical azadirachtin, widely used against above-ground insects, could become an option for the control of this soil insect pest. Methods Artificial diet-based bioassays were implemented under standard laboratory conditions to establish dose response curves for the pest larvae. Then, potted-plant experiments were implemented in greenhouse to assess feasibility and efficacy of a novel granular formulation of azadirachtin under more natural conditions and in relation to standard insecticides. Results Bioassays in three repetitions revealed a 3-day LD50 of 22.3 µg azadirachtin/ml which corresponded to 0.45 µg/neonate of D. v. virgifera and a 5-day LD50 of 19.3 µg/ml or 0.39 µg/first to second instar larva. No sublethal effects were observed. The three greenhouse experiments revealed that the currently proposed standard dose of a granular formulation of 38 g azadirachtin/hectare for in-furrow application at sowing is not enough to control D. v. virgifera or to prevent root damage. At 10× standard-dose total pest control was achieved as well as the prevention of most root damage. This was better than the efficacy achieved by cypermethrin-based granules and comparable to tefluthrin-granules, or thiamethoxam seed coatings. The ED50 for suppressing larval populations were estimated at 92 g azadirachtin/ha, for preventing heavy root damage 52 g/ha and for preventing general root damage 220 g/ha. Conclusions There seems clear potential for the development of neem-based botanical soil insecticides for arable crops such as maize. They might become, if doses are increased and more soil insecticides phased out, a promising, safer solution as part of the integrated pest management toolkit against soil insects.

Cost-effective bacteria-based bionematicide formula to control the root-knot nematode Meloidogyne spp. on tomato plants

Asyiah IN, Prihatin J, Hastuti AD, Winarso S, Widjayanthi L, Nugroho D, Firmansyah K, Pradana AP. 2021. Cost-effective bacteria-based bionematicide formula to control root-knot nematode Meloidogyne spp. in tomato plants. Biodiversitas 22: 3256-3264. The root-knot nematode, Meloidogyne spp. can infect and cause loss production in various horticultural plants, including tomatoes. In the previous study, we found 3 endophytic bacteria isolates and 1 rhizobacterium isolate that could control several plant-parasitic nematodes. In this study, we formulated these bionematicide isolates with cheap and environmentally friendly organic materials. The formula was fortified using several organic matters, vitamin sources, protein sources, and sugar sources. The research was conducted in an experimental land with a history of severe root-knot nematode infection. The analysis showed that there were 63.7 J2 Meloidogyne spp. per 100 ml of soil on the experimental land. The application was given at a time interval of 2 weeks at the concentration of 0.5%, 1%, 1.5%, and 2%, with a dose of 100 ml per plant. As a negative control, the plant did not give any treatments, and as a positive control, the plant was given 5 g carbofuran per plant. The results revealed that treatment with 2% bionematicide formula concentration showed the best consistent result. This treatment increased canopy wet weight by 38.63% and root dry weight by 106.97% compared to negative control. The P4 treatment was also found effective to increase fruit weight by 33.61% and fruit diameter by 26.16% as compared to negative control. Increased plant growth in P4 treatment was closely related to the total of root-knot suppression and root damage intensity. In the P4 treatment, the total of root-knots and root damage intensities was 44.83% and 32.66%, respectively, compared to the negative control. This suppression also occurred in the nematode population and nematode eggs. In the P4 treatment, the total of Meloidogyne spp. J2 in soil and root was lower by 60.74% and 66.24%, respectively, compared to the negative control. A similar phenomenon also occurred in the total of eggs, which was 79.40% lower than the total of eggs in the negative control. This study provides the latest information about a cost-effective bacteria-based bionematicide formula, which is effective in suppressing Meloidogyne spp. infection in tomato, and promotes the growth and development tomato plant.

Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs

Our previous study reported that fresh produce grown in aquaponic and hydroponic systems can pose potential food safety hazards due to an accidental introduction of contaminated fish and cross-contamination between the systems. In this study, we examined the effects of plant species and age on the likelihood and level of internalization of Shiga toxin-producing Escherichia coli (STEC) in aquaponic and hydroponic systems. Four plant species, basil (Ocimum basilicum L. cv. Genovese), cilantro (Coriandrum Sativum L.), lettuce (Lactuca sativa cv. Cherokee), and kale (Brassica oleracea var. sabellica), received root damage treatment as seedlings before transplanting or mature plants at three weeks after transplanting by cutting off 1-cm tips of one-third of the roots. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR for the presence of stx1 gene in plant tissues, recirculating water, and fish feces collected at four weeks after transplanting. In hydroponic systems, STEC was found neither in the solution nor in the roots and leaves of all four plant species, possibly through improved sanitation and hygiene practices. However, consistent with our previous findings, STEC was found in the water, on the plant roots, and in the fish feces in aquaponic systems, even after thorough sanitation prior to the study. Regardless of plant age, STEC was internalized in the roots of all plant species when the roots were damaged, but there was no difference in the degree of internalization with STEC among plant species. STEC was present in the leaves only when seedlings received root damage treatment and were grown to maturity, indicating that root damage allows STEC to internalize in the roots within a week, but a longer period is required for STEC to internalize into the leaves. We concluded that root damage on seedlings can cause the internalization of E. coli O157:H7 in the edible parts of leafy vegetables and herbs in soilless production systems.

High tolerance to simulated root herbivory in hydroponically grown cuttings of Salix phylicifolia

The shortage of information regarding the effects of root damage on forest plants, especially trees and shrubs, is the most critical gap in our knowledge of belowground insect herbivory. This study examines how the tea-leaved willow, Salix phylicifolia, responds to simulated root herbivory and how nutrient availability affects these responses. Hydroponically grown cuttings were used to precisely apply the desired levels of root damage. Root: shoot ratios increased proportionally to the intensity of root damage, whereas specific leaf area, leaf water content and chlorophyll fluorescence were not affected. The removal of 2–64% of roots once in early summer and the removal of 25% of roots three times during the summer did not change biomass production by cuttings. The repeated removal of 50 and 75% of roots decreased shoot biomass and, to a lesser extent, total root production. The tolerance of tea-leaved willow to root damage was greater in low nutrient treatment than in high nutrient treatment, thus supporting the Growth Rate Model. According to this model, in low resource conditions plants do not attain their maximum growth rate and therefore have a higher capacity for regrowth after damage. We conclude that, in the absence of water limitations, tea-leaved willow shows high tolerance to root losses and is unlikely to be affected by realistic levels of root herbivory.