Aims: Bakanae disease on rice has been widely distributed in all countries where rice is grown commercially, especially in Asian countries including Malaysia. As an alternative measure in controlling Fusarium fujikuroi, two approaches have to be adapted i.e. by using resistant varieties and biocontrol agents as reported in the present study. Methodology and results: A total of 31 Malaysian rice varieties were used in screening and results showed that variety MR211 was the most susceptible and MR220 was slightly susceptible. Out of 60 isolates of Trichoderma harzianum isolated from soils in Malaysia and tested against the pathogen under in vitro condition, 13 isolates showed high percentage of inhibition (PIRG > 60%). All isolates of T. harzianum showed that the PIRGs were significantly different at p≤0.05 with those of control plates. Conclusion, significance and impact of study: Biocontrol agent and resistant variety are better alternative for controlling plant diseases. We found a variety MR220 was slightly susceptible, but none of tested varieties is resistant towards pathogen of bakanae disease. T. harzianum has the ability to inhibit the growth of F. fujikuroi (T3068P) under in vitro condition. The findings of the Malaysian susceptible/resistant variety and potential T. harzianum isolate as a biocontrol agent of bakanae are important for future tests in the plant house and field trials.
Biological Control Agents ; Oryza

Aims: Cricula trifenestrata is one of natural insects which has not been domesticated yet, thus called as the wild silkworm. C. trifenestrata is known as a silk producer which has high economic and market value. However, the fungi attack on C. trifenestrata cocoon decreased quality and quantity of silk yarn. Chitinolytic bacteria have a high potential as biological control against pathogenic fungi. This research aimed to isolate, select, characterize, and identify chitinolytic bacteria as pathogenic fungi growth inhibitors on C. trifenestrata cocoon. Methodology and results: Chitinolytic bacteria was isolated from the uninfected and infected cocoon while fungi was isolated from the uninfected cocoon. Inhibition test was conducted by Fokkema method and chitinase activity was measured by Spindler method. A total of 36 chitinolytic bacteria and 10 suspected pathogenic fungi isolates have been isolated. Fungal pathogenicity test showed that isolate CSAJ.2 was suspected as fungal pathogen. In vitro inhibition test indicated that chitinolytic bacteria isolate BSEP.3 could inhibit the growth of pathogenic fungi CSAJ.2 with percentage of inhibition 50%. Isolate BSEP.3 showed highest chitinase activity (5.11 U/mL) at the 15th h. It able to inhibit the growth of pathogenic fungi with percentage of inhibition of 47.5% and 46.25%, respectively. Conclusion, significance and impact of study: Identification of bacteria targeted on 16S rRNA gene showed that isolate BSEP.3 had 98% identity with Bacillus amyloliquefaciens B5 while identification of fungi using ITS region of the rDNA showed that isolate CSAJ.2 had 100% identity with Trichoderma virens TV242. Chitinase crude extract was effective to be used as a biological control agent of T. virens CSAJ.2.
Chitinase ; Biological Control Agents

Aims: Phytophthora capsici and Fusarium solani are common fungal pathogens causing severe diseases that lead to economic loss in pepper industry, especially in Sarawak. In response to the infections, chemical approach is more common; nevertheless, biological control is more favorable to control fungal pathogens. Biological control approach greatly reduces the problems associated with chemical applications and it restores balance of the natural environment. Here we present the ongoing work to study the action of antagonistic bacteria, Bacillus sp. and Pseudomonas sp., that produce volatile and non-volatile antifungal compounds against P. capsici and F. solani on pepper plants. Methodology and results: A total of seven bacterial candidates were isolated from different locations and tested for their antagonistic properties against P. capsici and F. solani in a dual culture assay and extracellular metabolite test. Extracellular hydrolytic enzymes production was also monitored and followed by genotypic indentification. Preliminary antagonism tests indicated that bacterial isolate Pep3 and Pep4 inhibit up to 50% of the growth of P. capsici and F. solani as compared to the control. Subsequent investigation on extracellular hydrolytic enzyme production revealed that both bacterial isolates are capable of secreting hydrolytic enzymes. Microscopic and genotypic analyses identified the bacterial isolates Pep3 as Bacillus amyloliquefaciens (KJ461444) and Pep4 as Pseudomonas pachastrellae (KM460937). Conclusion, significance and impact of study: B. Amyloliquefaciens (KJ461444) and P. pachastrellae (KM460937) inhibited the growth of P. capsici and F. solani thus reflecting the potential of the produced metabolites to be purified and used in combating plant pathogenic fungi.
Biological Control Agents ; Fungi ; Antibiosis

Aims: Several harmful dinoflagellate species are widely found in Malaysian marine waters. These microalgae are capable of producing a variety of toxins that can intoxicate humans through consumption of contaminated seafood. Therefore, the present work aimed to investigate the potential of a marine bacterium sdPS-7 isolate as a biological control agent against Alexandrium minutum KB-5. Methodology and results: The isolate sdPS-7 was obtained from marine sediments in Malaysia and examined for its algicidal activity toward the toxic dinoflagellate A. minutum KB-5 in laboratory culture. Based on morphological and molecular characterization, this isolate was identified as Aeromonas hydrophila sdPS-7. Alexandrium minutum KB-5 cultures were exposed to cell free bacteria culture filtrate and the effect on dinoflagelate growth was evaluated based on direct cell counts in the treated samples compared to non-treated control cultures. The bacterial filtrate was treated at different temperatures, salinities and exposed to repeated freezing and thawing five times to study its algicidal activity stability thereafter. The results showed a potent inhibition of the growth of A. minutum KB-5. The strongest effect was observed when the bacterium culture filtrate was mixed with A. minutum KB-5 cultures that were in lag phase, resulting in 99% or higher mortality. The cell-free filtrate proved to be heat- stable when exposed to temperatures of 2 °C to 100 °C for one hour each. There was also no substantial salinity as well as (freezing – thawing) effect on the filtrate algicidal activity. Conclusion, significance and impact of study: This study illustrated the potential use of the marine bacterial Aeromonas hydrophila sdPS-7 filtrates in controlling the growth of the toxic dinoflagellate A. minutum KB-5.
Biological Control Agents ; Aeromonas hydrophila

Aims: The application of beneficial microbes is a suitable alternative to synthetic pesticides and fertilizers for agriculture. This study was aimed to evaluate the potential of a selected Trichoderma strain as a biocontrol agent against Rhizoctonia sp. and as a biofertilizer to improve paddy growth. Methodology and results: Four Bipolaris strains were identified via DNA barcoding as the cause of brown spot disease, whereas two Rhizoctonia strains were similarly identified as the cause of sheath blight disease in Brunei Darussalam. Eight Trichoderma strains were initially screened using confrontation assay and were found to substantially inhibit the growth of Rhizoctonia sp. Hybrid rice named BDR5 was treated with Trichoderma sp. UBDFM01 and/or Rhizoctonia sp. It was found that the selected strain showed the potential as a biofertilizer by significantly increasing the vigour index I, chlorophyll a, chlorophyll b, total chlorophyll and dry shoot weight of the rice plants. The pathogen negatively affected the plants by significantly reducing the vigour index II, chlorophyll a, chlorophyll a/b ratio, total chlorophyll, and total weight of grains. Trichoderma strain showed the potential as a biocontrol agent by significantly diminishing the negative effects of the pathogen on the chlorophyll a, chlorophyll a/b ratio and total chlorophyll. Conclusion, significance and impact of study This study highlights the potential of Trichoderma sp. UBDFM01 as a biocontrol agent against Rhizoctonia sp. and also as a biofertilizer for rice plants. In addition, this study is the first to provide DNA-based evidence of Bipolaris sp. and Rhizoctonia sp. as the fungi that caused rice diseases in Brunei Darussalam.
Trichoderma ; Biological Control Agents ; Fertilizers--microbiology

Aims: The development of an effective biocontrol formulation for inhibition of Ganoderma boninense, a well-known destructive pathogen in oil palm plantation is important to prolong the palm’s lifespan and reduce the losses due to this disease. In this paper, we present some new bioformulations with combination of different types of biocontrol agents in managing basal stem rot (BSR) disease. Methodology: The effectiveness of the treatments designed as T1 (Trichoderma harzianum + Lecanicillium spp. + Streptomyces sundarbansensis + Pseudomonas aeruginosa), T2 (Penicillium simplicissimum + Lecanicillium sp. + S. sundarbansensis + P. aeruginosa), T3 (P. simplicissimum + P. aeruginosa) and T4 (LEStani®) was evaluated through treatment on the oil palm seedlings artificial infected by G. boninense and the results were expressed in disease severity index (DSI), bole severity index (BSI) and ergosterol content. Conclusion, significance and impact of study All tested treatments (T1-T4) managed to control the severity of the Ganoderma infection from continuously increasing when the treatments were applied either one month before or after artificial inoculation. The disease severity of infected seedlings without treatments had increased for almost 2-fold at the end of the trial. Moreover, T1 had the greatest inhibition of G. boninense with the lowest ergosterol content (a bioindicator of Ganoderma colonization) detected (676.67 g/mL), which is about 1.9-fold lower than control (1273.33 ug/mL) without treatments and a BSI score of 1. Based on the effectiveness among the four tested biocontrol formulations, T1 is the most promising formulation to be further evaluated in the field for control of BSR disease. However, more research is needed in the future to estimate the effective amount for application in open environment.
Palm Oil ; Biological Control Agents ; Ganoderma

Aims: Metarhizium anisopliae is an entomopathogenic fungus (EPF) that exists naturally in the environment and potentially be used as a biological control agent against many insect pests. This study aims to evaluate the effect of nutrient additives on the yield and viability of M. anisopliae spore and to determine the optimum incubation period for maximum spore production. Methodology and results: In this study, M. anisopliae was cultivated by solid-state fermentation using rice as a growth medium. Three different nutrient additives were examined which aimed to maximize the production of M. anisopliae spores. Among the three nutrient additives evaluated, yeast (1.84 ± 0.04 g) supported better growth and spore production than molasses (0.58 ± 0.04 g) and palm oil (0.47 ± 0.09 g). The incubation period between 2-6 weeks produced higher spore yield (0.97 ± 0.02 g spores) at week 4 with a better spore viability (86.30 ± 0.45%) at week 2. Conclusion, significance and impact of study Hence, it is suggested that the optimum incubation period is between 2 and 6 weeks after inoculation, and M. anisopliae could be mass produced in large quantities on rice substrate with the addition of yeast as the nutrient additives.
Biological Control Agents ; Microbial Viability ; Metarhizium

Endophytic fungi strains (n = 81) were isolated from the leaves, barks, and fruits of Camellia oleifera from Hunan province (China) to delineate their species composition and potential as biological control agents of C. oleifera anthracnose. The fungi were identified by morphological and phylogenetic analyses. Fungal colonization rates of the leaves, barks, and fruits were 58.02, 27.16, and 14.81%, respectively. The isolates were identified as 14 genera, belonging to two subdivisions, Deuteromycotina and Ascomycotina; 87.65% of all isolates belonged to Deuteromycotina. The dominant species, occurring with a high relative frequency, were Pestalotiopsis sp. (14.81%), Penicillium sp. (14.81%), and Fusarium sp. (12.35%). The Simpson’s and Shannon’s diversity indices revealed the highest species diversity in the leaves, followed by the barks and fruits. The similarity index for the leaves versus barks comparison was the highest, indicating that the number of endophytic fungal species shared by the leaves and barks was higher than barks and fruits or leaves and fruits. Based on the results of dual culture experiments, only five strains exhibited antifungal activity against C. oleifera anthracnose pathogen, with isolate ty-64 (Oidium sp.) generating the broadest inhibition zones. Our results indicate that the endophytes associated with C. oleifera could be employed as natural agents controlling C. oleifera anthracnose.
Biological Control Agents ; Camellia* ; Colon ; Endophytes ; Fruit ; Fungi* ; Fusarium ; Penicillium

Based on the data of 56 kinds of diseases and drug use in 100 kinds of cultivated Chinese herbal medicines, this paper used frequency analysis method to count the types of diseases and their drug use characteristics, and systematically analyzed the status of drug registration and monitoring standards for disease prevention and control of Chinese herbal medicines. The results showed that 14 diseases such as root rot, powdery mildew, and drooping disease were common in the production of Chinese herbal medicines. Among the 99 pesticides reported, 67.68% were chemically synthesized, 23.23% were biological pesticides, and 9.09% were mineral pesticides. Among the reported pesticides, 92.93% of them were low toxic, with relative safety. However, 70% of the production drugs were not registered in Chinese herbal medicines, and the phenomenon of overdose was serious. The current pesticide residue monitoring standards does not match well with production drugs in China. Although the matching degree between Maximum Residue Limit of Pesticide in Food Safety National Standard(GB 2763-2021) and production drugs is more than 50%, there are few varieties of Chinese herbal medicines covered. The matching degree between Chinese Pharmacopoeia(2020 edition), Green Industry Standard of Medicinal Plants and Preparations(WM/T2-2004), and production drugs is only 1.28%. It is suggested to speed up the research and registration of Chinese herbal medicine production and further improve the pesticide residue limit standard combined with the actual production, so as to promote the high-quality development of Chinese herbal medicine industry.
Humans ; Biological Control Agents ; Drugs, Chinese Herbal ; Pesticide Residues ; Pesticides

Pseudostellaria heterophylla in large-scale cultivation needs to apply pesticides to control diseases, and non-standard use of pesticide may cause excessive pesticide residues in medicinal materials, increasing the risk of clinical medication. To accurately monitor the residual pesticides, this paper investigated the drug use during the process of P. heterophylla disease prevention in 25 P. he-terophylla planting enterprises or individual households in Guizhou province. It was found that there were 8 common diseases in P. he-terophylla planting, including leaf spot, downy mildew, virus disease, root rot, dropping disease, purple feather disease, white silk disease, and damping-off disease. Twenty-three kinds of pesticides were used in disease control, mainly chemical synthetic pesticides, accounting for 78.3%, followed by biological pesticides and mineral pesticides, accounting for 13.0% and 8.7%, respectively. The disease prevention and control drugs were all low-toxic pesticides, and there were no varieties banned in the Chinese Pharmacopoeia(2020 edition). However, the pesticides used have not been registered on P. heterophylla, and the excessive use of drugs was serious. The present monitoring of pesticide residues in P. heterophylla is mainly based on traditional pesticides such as organochlorine, organophosphorus, and carbamate, which does not effectively cover the production of drugs and had certain safety risks. It is suggested to speed up the research and registration of drug use in the production of P. heterophylla, increase the use of biological pesticides, and further improve the monitoring indicators of pesticide residues in combination with the actual production of drugs, so as to promote the high-quality development of P. heterophylla industry.
Biological Control Agents ; Caryophyllaceae ; Pesticide Residues ; Pesticides ; Plants, Medicinal