The research objective of the Crop Protection Division (CPD) focused on the development of technologies to help farmers improve their pest management decision-making towards rice self-sufficiency. Blast caused by Magnaporthe grisea [Herbert] Barr., is one of the most important rice diseases worldwide. Ecological engineering approach to pest management: Effect of vegetation corridor on the population of the different functional arthropod groups and insect damage in farmers' fields.
In other crops, the abundance and diversity of predators and parasites in the field is closely related to the nature of the vegetation at the edges of the field. These compounds are secondary metabolites known to be part of normal plant growth and development. Most important sources of resistance to major insect pests have been incorporated into lines that have improved plant species.
The result of the evaluation under screen house conditions (Table 5) in the 2016 DS showed that of the 541 entries, the majority were resistant to the brown planthopper (BPH) and the green leafhopper (GLH). Rice blast is caused by the fungus Pyricularia oryzae, which can infect several organs of the plant. Evaluations of deadheart (DH) in the remaining breeds showed that the majority of entries were mediocre.
Several factors influenced the initial outcome of the study over subsequent seasons; a thorough validation of the data for the next season is needed.
Biology and Ecology of Pests
Monthly population fluctuation of rice grain bugs caught in light trap in selected barangays of Kitcharao, Agusan Del Norte and Alegria. Rice grain bug population at different rice plant stages in Anibongan, Kitcharao, Agusan Del Norte from January to June 2016. Rice grain bug population at different rice plant stages in Anahaw, Alegria, Surigao del Norte from January to June 2016 harvest.
Population of rice grain fever at different stages of the rice plant in San Pedro, Alegria, Surigao del Norte from January to June 2016 cropping. It was also emphasized that the genetic lineages of the rice blast fungus are related to pathotypes with different cultivar specificity. The aim of the study is to a) assess the genetic diversity of isolates of the rice blast pathogen from different rice-growing regions of the Philippines (rainfed, upland, cool, saline and irrigated lowland); b) determine the variation between isolates as partitioned in space;.
Each of the blast DNA was subjected to PCR amplification and quality and quantity standardization at a run-in of 1.25%. Ten primers were optimized by changing the amount of the cocktail's different ingredients. Figures and 13 show the significant variation of the growth of Magnaporthe grisea in each of the solid media used.
Yellow stem borer is one of the widespread, dominant and monophagous pests of rice. It was observed that the high population of the mirid bug was only high during the peak of the hopper populations. Sorting, identifying and counting the samples collected by the light trap was carried out continuously in the Entomology Laboratory during the remaining months of the year to determine the peak population for the wet season.
Several studies have been conducted to determine the incidence and extent of weedy rice in some parts of the Philippines. Although these studies are limited and do not provide a complete picture of the extent of the spread of weedy rice in the Philippines, they indicate the increasing number of fields where weedy rice is found. A global positioning system (GPS) was used to map the distribution and to track the position of the areas where weedy rice was seen.
Three biotypes had purple colored grain tips, while the other 5 biotypes did not have purple colored tips. Thirteen biotypes had purple colored grain tips, 10 biotypes were not purple colored and 1 biotype had black brown colored grains.
Evaluation and Optimization of Fossil Fuel-Free–Rice Pest Management Strategies and Techniques
Population of adult rice bugs as affected by the application of Beauveria bassiana (January to June 2016). Total number of rice bugs infected with Beauveria bassiana after application of the fungus in the field. Yield (tonnes/ha) NSIC Rc212 as influenced by the application of Beauveria bassiana suspension in the field*.
However, no research is being done on the beneficial role that weedy rice could play in rice production. In 2014–2015, 20 weedy rice biotypes were screened for resistance to rice tungro disease (RTD) and bacterial leaf blight (BLB) to assess whether weedy rice could be used as a source of RTD and BLB resistance genes. In 2016 DS, a confirmatory trial was conducted on selected weedy rice biotypes in order to select parent materials recommended for breeding activities.
Six pre-selected weedy rice biotypes from Aurora, Pampanga, Pangasinan and Iloilo were re-evaluated for tungro resistance under induced method in greenhouse condition (2016 dry season). Thirteen pre-selected weedy rice biotypes from Negros, Pangasinan, Tarlac, Bulacan and Pampanga were re-evaluated for resistance to bacterial leaf blight (BLB) under greenhouse conditions (2016 dry season). Weedy rice biotypes were inoculated with BLB inoculum, cut 6 cm from the tip of the plant using the inoculation cutter at 30 and 45 DAS.
In 2016 wet season, hybridization was done between identified weedy rice with resistance to tungro and bacterial leaf blight (BLB). Generation of several crosses was done to evaluate the crossability of identified weedy rice resistant to RTD and BLB into adapted rice varieties. The selected weedy rice resistant to tungro and BLB (WR-B3, WR-B4, WR-ILO2 and ILO-3) were used as donor parent, while TN1 known for its susceptibility to both diseases and NSIC released varieties Rc160, Rc222 and Rc402, were selected as the recurrent parent or recipient of the resistance of weedy rice.
Pre-selected weedy rice biotypes showed resistance to RTD with a score of 0 to 40% infection when inoculated at 30 and 45 days after sowing (DAS). The weedy rice biotypes from Maria Aurora, Aurora Province (WR-B3) and Ilo-ilo (WR-Ilo2 and WR-Ilo3) had the lowest infestation of 0-10%. Weedy rice biotypes that had a resistant reaction (0-20% infection) in plants inoculated at 30 or 45 DAS were selected for breeding purposes.
The culture was incubated at 23oC for 7 to 14 days until either clear inhibition was observed or the colonies of the two fungi had come into contact. Meanwhile, various components of the rice agroecosystem, including paddy water, soil, rice, seed and its plant parts, have been found to be rich sources of antagonists against pathogens of rice such as Magnaporthe grisea, Rhizoctonia solani and Fusarium moniliforme. The phyllosphere, which is the plant's surface above ground, is a habitat rich in bacteria, fungi, yeasts and algae, all epiphytic microorganisms.
Considering this nature of the infection, the present study focused on screening potential antagonists of the rice blast pathogen from the phyllosphere of different rice varieties grown in rain-fed rice areas in different geographical locations in the Philippines and determining their efficiency in controlling of the development of rice blasts under greenhouse conditions. . The aim of this study is a) to isolate and evaluate potential epiphytic antagonists against the rice pathogen; (b) determining the effects of the potential antagonists against the rice pathogen under greenhouse conditions; c) evaluating and identifying the production of secondary metabolites of the potential antagonists; and d) characterizing and identifying the potential antagonists. Using the said collected samples, various epiphytic microorganisms (bacteria and fungi) were isolated and purified and stored at -20oC for further testing as potential antagonist of rice blast pathogen.
Epiphytes showing antagonistic activity against the rice pathogen were tested for their toxicity against rice (pathogenicity test) to ensure that it cannot harm the crop when used as an antagonist. Of the 216 isolates, 55 were subjected to an antagonist test, of which 25 were found to have antagonistic activity against the rice pathogen; those without antagonistic effect were eliminated, otherwise stored at -20oC and will be subjected to further testing. Figures 27 and 28 show some of the antagonistic efficacy of the selected purified epiphytes in a preliminary test.
This confirmed that epiphytes present in rice leaves have potential as biocontrol agents against rice blast disease-causing pathogen. Further testing of its antagonistic potential against the rice blast pathogen will be conducted to verify its efficacy in both in vitro and in vivo experiments. Each pair was replicated 5 times and the experiment was repeated three times to verify the result.
These showed that the 3 pathogens were not controlled by fungicide application compared to T5Oi and TMDRi which was more effective than fungicide application in inhibiting mycelial growth of the three test pathogens (Figure 31). Rice grain bug population at different stages of rice plant in Anibongan, Kitcharao, Agusan Del Norte from January to June 2016 planting season. Rice grain bug population at different stages of rice plant in Anahaw, Alegria, Surigao del Norte from January to June 2016 planting season.
Population of the rice grain bug at different stages of the rice plant in San Pedro, Alegria, Surigao del Norte from January to June 2016, harvest season. The culture was incubated at 23°C for 7 to 14 days until clear inhibition was observed or until the colonies of the two fungi had come into contact with each other.
