Management Of Rice Insect Pests Research Articles

Exploring the Utility of Light Traps for Early Detection and Management of Rice Insect Pests

Exploring the Utility of Light Traps for Early Detection and Management of Rice Insect Pests

IMPACT OF BIO-CONTROL AGENT ON THE MANAGEMENT OF RICE INSECT PESTS

Insect pests and disease infestations are the primary problems in rice (Oryza sativa) cultivation. Mostly lepidopteran and hemipteran like yellow stem borer and brown plant hopper respectively are the important insect pests. Concerns about chemical free agriculture have promoted widespread introduction of integrated pest management, an ecologically based approach to control the harmful insects and pests. Integrated pest management is intended to reduce ecological and health damage from chemical pesticides by using natural parasites and predators to control pest population. This review article describes the impact of various biocontrol agents with respect to management of rice insect pests.

Ecological Engineering for Rice Insect Pest Management: The Need to Communicate Widely, Improve Farmers’ Ecological Literacy and Policy Reforms to Sustain Adoption

Ecological engineering (EE) involves the design and management of human systems based on ecological principles to maximize ecosystem services and minimize external inputs. Pest management strategies have been developed but farmer adoption is lacking and unsustainable. EE practices need to be socially acceptable and it requires shifts in social norms of rice farmers. In many countries where pesticides are being marketed as “fast moving consumer goods” (FMCG) it is a big challenge to shift farmers’ loss-averse attitudes. Reforms in pesticide marketing policies are required. An entertainment education TV series was able to reach wider audience to improve farmers’ ecological literacy, shifting beliefs and practices. To sustain adoption of ecologically based practices organizational structures, incentives systems and communication strategies to support the new norms and practices are needed.

Frontier pest management technologies for sustainable rice production

Although effective management of rice insect-pests can be achieved by insecticides but their excessive long term use poses human health and environmental risks in addition to effect on non-targets organisms. Now-a-days, some pest management practices such as agronomic practices like smart fertilizer and nutrient application, real time monitoring and surveillance, ecological engineering through habitat manipulation, biological control by more effective strain, nanotechnology, host plant resistance by RNAi and marker assisted selection, have been introduced and adopted to manage rice insect pests which are eco-friendly in nature and also promote natural pest management. Here, this article intended to discuss the various frontier pest management technologies which will help for sustainable rice production.

Salinity Influences Plant-Pest-Predator Tritrophic Interactions.

Climate change-induced salinity intrusion into agricultural soils is known to negatively impact crop production and food security. However, the effects of salinity increase on plant-herbivore-natural enemy systems and repercussions for pest suppression services are largely unknown. Here, we examine the effects of increased salinity on communities of rice (Oryza sativa), brown planthopper (BPH), Nilaparvata lugens, and green mirid bug (GMB), Cyrtorhinus lividipennis, under greenhouse conditions. We found that elevated salinity significantly suppressed the growth of two rice cultivars. Meanwhile, BPH population size also generally decreased due to poor host plant quality induced by elevated salinity. The highest BPH density occurred at 2.0 dS/m salinity and declined thereafter with increasing salinity, irrespective of rice cultivar. The highest population density of GMB also occurred under control conditions and decreased significantly with increasing salinity. Higher salinity directly affected the rice crop by reducing plant quality measured with reference to biomass production and plant height, whereas inducing population developmental asynchrony between BPH and GMB observed at 2 dS/m salinity and potentially uncoupling prey-predator dynamics. Our results suggest that increased salinity has harmful effects on plants, herbivores, natural enemies, as well as plant-pest-predator interactions. The effects measured here suggest that the bottom-up effects of predatory insects on rice pests will likely decline in rice produced in coastal areas where salinity intrusion is common. Our findings indicate that elevated salinity influences tritrophic interactions in rice production landscapes, and further research should address resilient rice insect pest management combining multipests and predators in a changing environment.

Impacts of plant spacing and nitrogen fertiliser on incidences and density of spotted and African pink stem borers in Tanzania

Nitrogen fertilisation and plant spacing hold potential for the integrated management of rice insect pests. Field experiments were conducted in Kilombero, Tanzania to evaluate the effects of plant spacing and nitrogenous fertiliser on incidences and density of spotted and African pink stem borers. A 3 × 4 × 4 factorial experiment was used in a randomized complete block design with three replications. Treatments included application of urea fertiliser at four levels (0, 40, 80, and 160 kg N ha−1) and spacing at four levels (10 cm × 10 cm, 15 cm × 15 cm, 20 cm × 20 cm, and 25 cm × 25 cm). Nitrogen significantly increased dead hearts by 4.8%, white heads by 2.8% and stem borer larvae density from 0 to 5.6 larvae/m2. Decreasing the planting density significantly increased dead hearts by 4.7%, white heads by 2.7% and stem borer larvae density from 0 to 5.4 larvae/m2. The interaction of nitrogen fertiliser rates and plant spacing did not affect stem borer incidences nor larvae density, but did influence the rice yield.

Species composition of parasitoids and predators in two rice agro-farming systems—effect of ecological intensification

Ecological intensification through organic farming is known to have an influence on plant communities and diversity of insects associated with them. The comparative abundance of natural enemies was studied in organically as well as conventionally (chemical control) grown aromatic rice at farmer’s field during 2015–2016 and 2016–2017. Different life stages, i.e., egg, larvae and pupae of rice stem borer, and leaf folder, were collected and brought to the laboratory to record natural parasitism in both organic and conventional fields. The population of predators was recorded through sweep nets. The population of spiders was recorded using pitfall traps and sweep net. A total of nine parasitoid species including 3 egg parasitoids (T. chilonis, T. japonicum, and Telenomus sp.), 3 larval parasitoids (Stenobracon nicevillei, Bracon sp., and Cotesia sp.), and 3 pupal parasitoids (Tetrastichus sp., Brachymeria sp., and Xanthopimpla sp.) were recorded. However, the natural parasitism by these parasitoids was significantly higher in organic than conventional rice. Similarly, the population of predators like spiders, dragonflies, and damselflies was significantly higher in organic fields than in conventional fields. The study highlights the significance of conservation of these natural enemies for a sustainable system of rice insect pest management.

Evaluation of various IPM modules against foliage feeding insect-pests of Rice

Five Integrated Pest Management (IPM) modules were tested along with untreated control against the foliage feeding insects in rice. Over two years, the IPM module having nursery treatment with fipronil 0.3G @ 20 kg/ha + chlorantraniliprole 0.4G @ 10 kg/ha at 40 days after transplanting + buprofezin 25% SC @ 825 ml/ha foliar spray at 65 days after transplanting proved to be most effective in controlling leaf folder and case worm having highest benefit cost ratio (1.89). The treatment module constituting nursery treatment with fipronil 0.3G @ 20 kg/ha + Trichogramma japonicum + Beauveria bassiana @ 2 lt/ha foliar spray at 30 and 50 days after transplanting + neem seed kernel extract (5%) spray at 65 days after transplanting’ performed second best with respect to leaf folder and caseworm management; however showed superiority in suppressing hispa and whorl maggot, achieved benefit cost ratio (1.71). In the present context of increasing trend of insecticide resistance by the pests and environmental hazards, this experiment had the interesting finding that biopesticides, botanicals and green level pesticides can be a safe alternative which can compensate the efficacy of conventional pesticides in the management of rice insect pests.

Economic and ecological perspectives of farmers on rice insect pest management.

Understanding farmers’ perception is important in the development of sustainable and cost-effective integrated pest management strategies. Hence, farmers’ perception on rice insect pests and pesticide use was evaluated by selected 112 farmers composed of 77% males and 23% females, over the rice growing areas of North Cotabato, Central Mindanao, Philippines. 62% of farmers that were interviewed use pesticides based on the presence of pests. These farmers identified white stem borer and rice leaf folder as the most encountered insect pests on the local rice crops. Due to these insect pests, rice production became constrained producing low income for the farmers. Pesticide application was perceived to be effective (73%) but not efficient in controlling insects. Moreover, farmers recognized the negative effects of pesticide applications in the environment (76%). However, in spite of these expensive pest control strategies, local farmers still agreed (83%) to apply these methods to increase rice production and their income. With the advantage of using pesticides to boost production over the harm it can cause, farmers would not agree to stop (39%) or still are undecided (23%) to reduce pesticide application. Thus, efficient, safe, low cost pest control strategies are needed to reduce reliance of farmers to pesticides and to improve agricultural production and food security of smallholder farmers in the Philippines.

Paradigm shift of insect pests in rice ecosystem and their management strategy

Insect population has changed both spatially and temporally over the period of time in a crop like rice. In the present study, data from the year 1965 to 2017 shows considerable increase of insect pests to 21 numbers. Their spread to large rice areas has been worked out which is a matter of concern, particularly Brown Planthopper (BPH), which has invaded all rice growing areas of the country. Present article focuses on more frequent occurrence of pests in different years related to the extent of damage incurred, which will be the principal concern of applied entomologists and farmers. Insects are classified as pests based not solely on numbers but on socioeconomic impact and on biological tolerance of the host to pest attack. In the present study, emphasis is placed upon host plant resistance to pests, proper monit oring and developing location-specific IPM packages for management of rice insect pests based on their initial populations and the processes by which they change to endemic form.

Validation of Integrated Pest Management Practices for Rice Insect in North-west Region of Bangladesh

Integrated Pest Management (IPM), developed by the Bangladesh Rice Research Institute (BRRI) for management of rice insect pests, was demonstrated and validated through intensive investigation in farmer’s fields of Pirganj and Taraganj in Rangpur district during 2012–2014 in two T. Aman and Boro seasons. A portion of each farmer’s field kept under the respective farmers’ supervision without any intervention, which was treated as control treatment (T4). The other portion was managed with three treatment combinations ie, T1=Prophylactic use of insecticide, T2=Perching + sweeping + need based insecticide application and T3=Perching only. BRRI dhan52 and BRRI dhan58 were used in Aman and Boro seasons respectively. RCB design was followed with eight replications for data analysis. The insect infestation was monitored fortnightly by visual counting from 20 hills and also 20 complete sweeps. The insect infestation, yield and yield contributing characteristics were analysed by one way analysis of variance by Tukeys’ post hoc test. The objective of this studies were to validate and demonstrate the IPM techniques in farmers' field. Yellow stem borer, rice leaf roller, long horned cricket, grasshopper, green leafhopper, brown planthopper, white-backed planthopper and gall midge were found as pests in both the locations. However, insect infestation was below the economic threshold level (ETL). No significant differences were observed for insect infestation among the treatments. Natural enemies eg, spider, ladybird beetle, dragon fly, damsel fly, carabid beetle and staphylinid beetle were noticed in both the locations. In some seasons and also locations some natural enemies were not found particularly where indiscriminate/continuous insecticide was used. Thus, it was indicated that indiscriminate/continuous use of insecticide has the detrimental effect on the population of natural enemies. Also, refrained from insecticide application at early crop stages (30-40-day after transplanting) natural enemy populations increased, which might reduce insect population below the ETL. Significantly lower yield was observed at farmers managed fields in both the locations. Therefore, it was found that indiscriminate/continuous use of insecticide had no effect on yield and yield contributing characters of rice, when insect infestation below the ETL. So, farmers could avoid continuous/indiscriminate use of insecticide, which might ultimately save production cost and the environment from insecticidal pollution as well.Bangladesh Rice j. 2015, 19(1): 17-31

The insect ecdysone receptor is a good potential target for RNAi-based pest control.

RNA interference (RNAi) has great potential for use in insect pest control. However, some significant challenges must be overcome before RNAi-based pest control can become a reality. One challenge is the proper selection of a good target gene for RNAi. Here, we report that the insect ecdysone receptor (EcR) is a good potential target for RNAi-based pest control in the brown planthopper Nilaparvata lugens, a serious insect pest of rice plants. We demonstrated that the use of a 360 bp fragment (NlEcR-c) that is common between NlEcR-A and NlEcR-B for feeding RNAi experiments significantly decreased the relative mRNA expression levels of NlEcR compared with those in the dsGFP control. Feeding RNAi also resulted in a significant reduction in the number of offspring per pair of N. lugens. Consequently, a transgenic rice line expressing NlEcR dsRNA was constructed by Agrobacterium- mediated transformation. The results of qRT-PCR showed that the total copy number of the target gene in all transgenic rice lines was 2. Northern blot analysis showed that the small RNA of the hairpin dsNlEcR-c was successfully expressed in the transgenic rice lines. After newly hatched nymphs of N. lugens fed on the transgenic rice lines, effective RNAi was observed. The NlEcR expression levels in all lines examined were decreased significantly compared with the control. In all lines, the survival rate of the nymphs was nearly 90%, and the average number of offspring per pair in the treated groups was significantly less than that observed in the control, with a decrease of 44.18-66.27%. These findings support an RNAi-based pest control strategy and are also important for the management of rice insect pests.