When discussing the compatibility of Bacillus thuringiensis (Bt), it’s important to understand that its effectiveness can be influenced by a wide range of factors. The entomopathogenic properties of Bt arise from its toxic spores and the insecticidal crystal protein complexes they produce. There has been a significant focus in the field on the manipulation of these components to enhance the potency and stability of Bt formulations.
The synergistic effect of Bt can be greatly impacted by various factors such as adjuvants, application methods, agitation modes, solvents, pH levels, temperature, and UV intensity. By incorporating enhancers, which may be organic or inorganic compounds without insecticidal properties on their own, it’s possible to elevate the internal pH of insects, activate protease enzymes, and subsequently, boost the activity or solubility of insecticidal crystal proteins. For example, the addition of sucrose, chitinase, and ascorbic acid has been found to improve the effectiveness of Bt against cotton bollworms. Similarly, the incorporation of MgSO4, CaCl2, and citric acid can augment the efficacy of Bt HBF-1, while MgCl2 and K2CO3 have been recognized for their significant role in enhancing the pest control effectiveness of Bt.YJ-2000 against pests like the diamondback moth and the armyworm.
The compatibility of Bt with different formulations or insecticidal toxins can result in enhanced killing power. For instance, the combination of CryIAa and CryIAc toxins displays synergistic effects on gypsy moths. Additionally, the simultaneous use of Bt products and β-exotoxins has been found to enhance the pest control effects against fall armyworms. The combined application of Bt.MPU.B6 and Bt.MPU B9 proteins has shown increased effectiveness against the Colorado potato beetle.
Innovative approaches, such as the use of nanomaterials alongside pesticides, have shown promise in efficiently improving the insecticidal effects. Nanotechnology can function as a vector to enhance dispersibility and stability, thus safeguarding Bt proteins from the interference of the insect gut’s proteolytic and lysosomal actions. Furthermore, nanomaterials as carriers could help improve toxicity against non-sensitive pests.
Finding suitable synergists is crucial for developing safe, potent, green, and environmentally friendly Bt pesticides. The enhancement mechanisms largely pertain to improving the Bt formulation’s appeal to target insects, altering the adversary’s midgut pH to amplify Bt toxin activity, improving the specific binding capacity of Bt proteins, and disrupting the insect’s intestinal integrity to promote the spread of the active Bt components.
However, the mechanisms behind the synergistic interaction of Bt with synergists require further elucidation. Research is also expanding into the impactful integration of Bt with other pesticides for pest control. Synergistic mixtures of pesticides, adjuvants, and additives can yield amplification effects on pest control that surpass mere addition of their individual toxicities. Nevertheless, improper combinations with Bt can also reduce its effectiveness.
An investigation into Bt and its combinations with various agents is ongoing, with evidence indicating that a several fungicides can reduce the potency of Bt. There’s evidence of suppression, as seen with insecticides like chlorantraniliprole and indoxacarb affecting Bt strains. Moreover, substances like azadirachtin and cyantraniliprole have been identified to antagonize the effects of Bt formulations, thereby diminishing pest control efficacy.
Understanding the characteristics of the agents involved in Bt combinations is imperative for effective pest control. Although most studies focus on the application outcomes, there is a scarcity in the literature regarding the underlying mechanisms of interactions between Bt and other pesticides. Conducting deeper research into these interactions is significant for enhancing the insecticidal properties of Bt products, reducing or delaying the increase in insect resistance, and minimizing the residue of agricultural production and environmental pollution.