Nevin Ahmed

Bitter gourd has picked up noteworthy consideration for its pharmacological benefits. However, the impact of amino acids (AAs) dosage on growth, yield, and antioxidants is uncertain. In this study, we investigated the effects of foliar spraying bitter gourd with 100, 200, and 300 mg/L dosages of tryptophan (Trp), glutamine (Gln), and phenylalanine (Phe). The results revealed that Trp, at a dosage of 300 mg/L, produced the most substantial increase in plant length, followed by 300 mg/L Phe. Additionally, the highest values of the fresh dry weight of the plants, fresh weight of the first fruit, fruit number per plant, fresh weight of the fruits per plant, and total fruit output per hectare were seen at 300 mg/L of Trp, followed by 300 mg/L of Gln. Phe at 300 mg/L yielded the highest levels of total phenolics and total flavonoids, coupled with strong scavenging activity against 2,2-diphenyl-1-picrylhydrazyl. These outcomes show the potential of Trp and Gln foliar sprays to enhance bitter gourd growth, yield, and certain antioxidant compounds. These findings carry substantial implications for the enhancement of bitter gourd cultivation and quality. By revealing AA’s potential for improving bitter gourd, our research contributes to bolstering the agricultural sustainability of this remarkable crop.

The house fly Musca domestica L. is one of the medical and veterinary pests that can develop resistance to different insecticides. Mixing insecticides is a new strategy for accelerating pest control; furthermore, it can overcome insect resistance to insecticides. This study aims to evaluate three insecticides, chlorfenapyr, abamectin, and lambda-cyhalothrin, individually and their binary mixtures against 2nd instar larvae of M. domestica laboratory strain. Chlorfenapyr exhibited the most toxic effect on larvae, followed by abamectin then the lambda-cyhalothrin. The half-lethal concentrations (LC₅₀) values were 3.65, 30.6, and 94.89 ppm, respectively. These results revealed that the high potentiation effect was the mixture of abamectin/chlorfenapyr in all the mixing ratios. In contrast, the tested combination of lambda-cyhalothrin/abamectin showed an antagonism effect at all mixing ratios against house fly larvae. The total protein, esterases, glutathione-S-transferase (GST), and cytochrome P-450 activity were also measured in the current investigation in the larvae treated with chlorfenapyr. Our results indicate that GST may play a role in detoxifying chlorfenapyr in M. domestica larvae. The highest activity of glutathione-S-transferase was achieved in treated larvae with chlorfenapyr, and an increase in cytochrome P-450 activity in the larvae was observed post-treatment with Abamectin/chlorfenapyr.

The two-spotted spider mite, Tetranychus urticae, also known as the red spider, is one of the most harmful pests in agriculture and causes large losses of many crops. These mites have rapidly developed a resistance to many chemical pesticides in recent years. In this study, the essential oil of seeds of the anise plant (Pimpinella anisum) was extracted by hydrodistillation, and the chemical composition of the oil was analyzed. The antioxidant activity of the volatile oil was determined by the DPPH radical scavenging assay. The acaricidal activity of the anise oil, a natural acaricide, was evaluated for its ability to protect green bean plants from mite injury. The two-spotted spiders were spread on green bean seedlings for 1 week; then, different plants were sprayed with different concentrations of anise oil (10, 20, 30, or 40 µL/L). Our results revealed that anethole was the major component of anise oil, at 53.23%. The acaricidal effect of the various concentrations on T. urticae was recorded after 24, 48, and 72 h of treatment. Our findings suggest that anise oil showed significant acaricidal activity against T. urticae in a dose- and time-dependent manner. Anise oil at a concentration of 40 µL/L killed 96.0% of the red spiders after 72 h. Also, all concentrations of anise oil inhibited acetylcholinesterase, and the spiders’ protease activity declined when the plants were treated with 30 or 40 µL/L of anise oil. The concentrations of 10 and 20 µL/L did not significantly affect the protease activity of T. urticae mites. We can conclude that anise oil exhibited acaricidal activity against T. urticae and that this was highly correlated with the inhibition of acetylcholinesterase and protease activities in the mites.

In this investigation, the impact of the predatory mite, Phytoseiulus persimilis (PM) and entomopathogenic fungus, Isaria fumosorosea (F) at three levels (F1=104, F2=106 and F3=108 conidia/ml) alone or in grouping state as compared with Ortus (acaricide) was evaluated on eggs and motile stages of two-spotted spider mites (TSSM). Nine treatments (CK=control, F1, F2, F3, PM, F1+PM, F2+PM, F3+PM and Ortus) were performed. On the other hand, the effect of the used entomopathogenic fungus on numbers of eggs and motile stages of the predatory mite was detected only at four treatments (PM, PM+F1, PM+F2, and PM+F3). Applications of I. fumosorosea at all chosen doses caused significant decreases in the mean population density of TSSM eggs (50.15-58.81% in 2016 and 59.63-68.37% in 2017) and motile stages (62.61-74-66% in 2016 and 68.47-75.32%) in comparison to the control. The effect of PM addition on TSSM eggs was higher than that of I. fumosorosea using but on TSSM motile stages, the pattern differed. The combination of both I. fumosorosea and P. persimilis showed greater influence on TSSM eggs and motile stages than the use of I. fumosorosea or P. persimilis individually. Spraying I. fumosorosea with releasing P. persimilis led to small reductions in eggs (11.88-22.42% in 2016 and 7.86-21.73% in 2017), and motile stages (9.84-21.33% in 2016 and 6.75-17%) of P. persimilis. Results of this study concluded that the combination of entomopathogenic fungus, I. fumosorosea and predatory mite, P. persimilis was strongly succeeded in the biological control process of TSSM on soybean plants under field conditions.

A pot trial was conducted to estimate the role of Trichoderma harzianum alone or in combination with two organic substances, potassium humate and chitosan in controlling Meloidogyne incognita on tomato. All treatments caused greater decreases in parameters of M. incognita in comparison to the control treatment (nematode only) and this led to noticeable enhancements in growth and yield of tomato. The lowest numbers of eggmasses, eggs/eggmass, galls/root, females/root, and second stage juveniles/250 g soil were recorded due to the combination of T. harzianum (10¹⁰ spore/ml) with chitosan and potassium humate after 120 days from the transplanting of tomato seedlings. Also, this treatment showed the best promotion for all tomato parameters (lengths and weights of shoots and roots, and productivity). So, mixing chitosan, potassium and T. harzianum is highly recommended to be used as an effective bio-nematicide against M. incognita on tomato plants.