4. Efficiency of diatomaceous earth for control of Mexican bean weevil (Zabrotes subfasciatus Boheman)

The results show that all doses of diatomaceous earth (DE) exerted an excellent control, such that in the evaluations registered at 15 days after application; 100% mortality was recorded in doses 4.0 and 5.0 g kg<sup>1</sup> , similar to those observed with the chemical control (deltamethrin). The doses of 2.0 and 3.0 g kg<sup>1</sup> of DE caused 95 and 96% mortality, in adults of Zabrotes subfasciatus. The dose of 1.0 g of DE caused 93% mortality, without statistical differences between the averages obtained with doses of DE and deltamethrin (Table 6), although these averages were significantly different from the average observed in the absolute control. The same behavior was observed in the evaluations recorded at 30, 45, and 60 daa (Table 6), where it can be seen that all DE doses used for pest control caused mortalities higher than 90%; this indicates that although the period of exposure was 2 months, mortality rates were maintained at 100% with the doses of 3.0, 4.0, and 5.0 g kg<sup>1</sup> of DE and deltamethrin at dose 1.0 mL kg<sup>1</sup> of seed. The lowest doses (1.0 and 2.0 g kg<sup>1</sup> ) also exerted excellent control of Zabrotes subfasciatus Boh., with statistical differences in mortality only in relation to that obtained in the absolute control.

The results of the first experiment served to make the decision to perform a second experiment with lower doses that were 0.2, 0.4, 0.6, 0.8, and 1.0 g kg<sup>1</sup> DE, 0.1 mL kg<sup>1</sup> Deltamethrin (chemical) and an absolute control (without application). The results indicated that at 10 daa DE, the doses of 0.6, 0.8, and 1.0 g kg<sup>1</sup> of seed resulted in 100% mortality (Table 7), similar to that caused by the chemical control (deltamethrin), without significant differences between the averages. However, these mortality rates were significantly different from those at 0.2 and 0.4 g kg<sup>1</sup> of seeds, and even more with respect to the percentage of mortality (0) in the absolute control. At 20 daa, it was observed that where doses of 0.6, 0.8, and 1.0 g kg<sup>1</sup> of DE and 0.1 mL kg<sup>1</sup> of deltamethrin (chemical) were applied, mortality rates were 100% for adult weevil of the bean, but were not significantly different to the 95% that was achieved with the dose of 0.4 g kg<sup>1</sup> of DE. However, if they were statistically different from the mortality (28% less) of that was achieved with the dose of 0.2 g kg<sup>1</sup> of DE, likewise, with respect to the 0% observed in the absolute control.

Seed germination was similar with all treatments applied, including the absolute control, with a seedling emergence ranging from 94 to 96%, considered as normal, and it was assumed that

\*Means with different letters in each column are statistically different, according to Tukey test (α ≤ 0.05); dda = days after

Table 7. Percentage of adult mortality of bean beetle (Zabrotes subfasciatus Boh.) treated with lower doses of

Absolute control 0.0 d\* 0.0 c 0.0 c 0.0 c Deltamethrin/0.1 mL kg<sup>1</sup> 100 a 100 a 100 a 100 a DE/0.2 g kg<sup>1</sup> 62.0 c 72.0 b 79.0 b 83.0 b DE/0.4 g kg<sup>1</sup> 90.0 b 95.0 a 97.0 a 98.0 a DE/0.6 g kg<sup>1</sup> 100 a 100 a 100 a 100 a DE/0.8 g kg<sup>1</sup> 100 a 100 a 100 a 100 a DE/1.0 g kg<sup>1</sup> 100 a 100 a 100 a 100 a

10 dda 20 dda 30 dda 40 dda

http://dx.doi.org/10.5772/intechopen.71534

11

Biorational Insecticides and Diatomaceous Earth for Control Sustainability of Pest in Chickpea and Mexican…

These results coincide with the results of Mikami et al. [27], where it is pointed out that diatomaceous earth is a mineral with insecticidal potential against the bean weevil, applied in doses of 1.0 g kg<sup>1</sup> to have a 100% mortality of the 3–8 days after application. They also coincide with those of [12, 14, 28, 29], since they report that these inert powders have been used with great success in controlling large numbers of stored grain pests, among which are Oryzaephilus surinamensis, R. dominica, Tribolium castaneum, T. confusum, Cryptolestes ferrugineus, S. zeamais, S. granarius, S. oryzae, Prostephanus truncatus, Acanthoscelides obtectus, and Zabrotes subfasciatus. It is reported that diatomaceous earth doses of 0.5, 1.0, and 2.0 kg per ton of maize seed alone and combined with deltamethrin synergized with piperonyl butoxide cause mortality higher than 97% of maize weevil, up to 120 days after application [30], and this same

In addition, they agree with those of [31], because they indicate that diatomaceous earth is an alternative for the control of Zabrotes subfasciatus Boheman, since after 5 days of exposure and temperatures of 27–30C, they had mortality of 100% with all the applied doses (0.5, 0.75, and 1.0 g kg<sup>1</sup> of seed), concluding that the suitable doses for the control of this pest of the store are

Mineral powders such as zeolite can control stored grain pests such as Sitophilus oryzae, Tribolium confusum, and Oryzaephilus surinamensis, and that therefore, this material can be successfully used as a grain and seed protector [32]. Likewise it is reported that inert dusts cause abrasive effects on the cuticle of insects, resulting in loss of water and, consequently, death [33, 34]. In addition, these powders may be used in combination with other products,

behavior was observed when it was combined with the insecticide deltamethrin.

such as vegetable powders to increase the efficacy of pest control.

the diatomaceous earth had no effect on the seed germination.

Treatment/doses Mortality (%)

application.

diatomaceous earth (DE).

those of 0.75 and 1.0 g kg<sup>1</sup> of seed.

At 40 daa, the treatments in doses of 0.6, 0.8, and 1.0 g kg<sup>1</sup> of DE and 0.1 mL kg<sup>1</sup> of deltamethrin, the mortality was 100% (Table 7), without significant difference with that caused by the dose of 0.4 g kg<sup>1</sup> of DE. However, these percentages were significantly different from the mortality that occurred with the dose of 0.2 g kg<sup>1</sup> of DE and with the absolute control.


\*Means with different letters in each column are statistically different, according to Tukey test (α ≤ 0.05); dda = days after application.

Table 6. Percentage of adult mortality of bean weevil (Zabrotes subfasciatus Boh.) treated with diatomaceous earth (DE).


between the averages obtained with doses of DE and deltamethrin (Table 6), although these averages were significantly different from the average observed in the absolute control. The same behavior was observed in the evaluations recorded at 30, 45, and 60 daa (Table 6), where it can be seen that all DE doses used for pest control caused mortalities higher than 90%; this indicates that although the period of exposure was 2 months, mortality rates were maintained at 100% with the doses of 3.0, 4.0, and 5.0 g kg<sup>1</sup> of DE and deltamethrin at dose 1.0 mL kg<sup>1</sup> of seed. The

statistical differences in mortality only in relation to that obtained in the absolute control.

The results of the first experiment served to make the decision to perform a second experiment with lower doses that were 0.2, 0.4, 0.6, 0.8, and 1.0 g kg<sup>1</sup> DE, 0.1 mL kg<sup>1</sup> Deltamethrin (chemical) and an absolute control (without application). The results indicated that at 10 daa DE, the doses of 0.6, 0.8, and 1.0 g kg<sup>1</sup> of seed resulted in 100% mortality (Table 7), similar to that caused by the chemical control (deltamethrin), without significant differences between the averages. However, these mortality rates were significantly different from those at 0.2 and 0.4 g kg<sup>1</sup> of seeds, and even more with respect to the percentage of mortality (0) in the absolute control. At 20 daa, it was observed that where doses of 0.6, 0.8, and 1.0 g kg<sup>1</sup> of DE and 0.1 mL kg<sup>1</sup> of deltamethrin (chemical) were applied, mortality rates were 100% for adult weevil of the bean, but were not significantly different to the 95% that was achieved with the dose of 0.4 g kg<sup>1</sup> of DE. However, if they were statistically different from the mortality (28% less) of that was achieved with the dose of 0.2 g kg<sup>1</sup> of DE, likewise, with respect to the 0% observed in the

At 40 daa, the treatments in doses of 0.6, 0.8, and 1.0 g kg<sup>1</sup> of DE and 0.1 mL kg<sup>1</sup> of deltamethrin, the mortality was 100% (Table 7), without significant difference with that caused by the dose of 0.4 g kg<sup>1</sup> of DE. However, these percentages were significantly different from the mortality that occurred with the dose of 0.2 g kg<sup>1</sup> of DE and with the

Absolute control 1.2 b\* 1.2 b 1.2 b 2.5 b Deltamethrin/1.0 mL kg<sup>1</sup> 100 a 100 a 100 a 100 a DE/1.0 g kg<sup>1</sup> 93.0 a 93.0 a 93.0 a 98.7 a DE/2.0 g kg<sup>1</sup> 95.0 a 97.5 a 97.0 a 98.7 a DE/3.0 g kg<sup>1</sup> 96.0 a 97.5 a 97.0 a 100 a DE/4.0 g kg<sup>1</sup> 100 a 100 a 100 a 100 a DE/5.0 g kg<sup>1</sup> 100 a 100 a 100 a 100 a

\*Means with different letters in each column are statistically different, according to Tukey test (α ≤ 0.05); dda = days after

Table 6. Percentage of adult mortality of bean weevil (Zabrotes subfasciatus Boh.) treated with diatomaceous earth (DE).

15 dda 30 dda 45 dda 60 dda

) also exerted excellent control of Zabrotes subfasciatus Boh., with

lowest doses (1.0 and 2.0 g kg<sup>1</sup>

10 Insecticides - Agriculture and Toxicology

absolute control.

absolute control.

application.

Treatment/doses Mortality (%)

\*Means with different letters in each column are statistically different, according to Tukey test (α ≤ 0.05); dda = days after application.

Table 7. Percentage of adult mortality of bean beetle (Zabrotes subfasciatus Boh.) treated with lower doses of diatomaceous earth (DE).

Seed germination was similar with all treatments applied, including the absolute control, with a seedling emergence ranging from 94 to 96%, considered as normal, and it was assumed that the diatomaceous earth had no effect on the seed germination.

These results coincide with the results of Mikami et al. [27], where it is pointed out that diatomaceous earth is a mineral with insecticidal potential against the bean weevil, applied in doses of 1.0 g kg<sup>1</sup> to have a 100% mortality of the 3–8 days after application. They also coincide with those of [12, 14, 28, 29], since they report that these inert powders have been used with great success in controlling large numbers of stored grain pests, among which are Oryzaephilus surinamensis, R. dominica, Tribolium castaneum, T. confusum, Cryptolestes ferrugineus, S. zeamais, S. granarius, S. oryzae, Prostephanus truncatus, Acanthoscelides obtectus, and Zabrotes subfasciatus. It is reported that diatomaceous earth doses of 0.5, 1.0, and 2.0 kg per ton of maize seed alone and combined with deltamethrin synergized with piperonyl butoxide cause mortality higher than 97% of maize weevil, up to 120 days after application [30], and this same behavior was observed when it was combined with the insecticide deltamethrin.

In addition, they agree with those of [31], because they indicate that diatomaceous earth is an alternative for the control of Zabrotes subfasciatus Boheman, since after 5 days of exposure and temperatures of 27–30C, they had mortality of 100% with all the applied doses (0.5, 0.75, and 1.0 g kg<sup>1</sup> of seed), concluding that the suitable doses for the control of this pest of the store are those of 0.75 and 1.0 g kg<sup>1</sup> of seed.

Mineral powders such as zeolite can control stored grain pests such as Sitophilus oryzae, Tribolium confusum, and Oryzaephilus surinamensis, and that therefore, this material can be successfully used as a grain and seed protector [32]. Likewise it is reported that inert dusts cause abrasive effects on the cuticle of insects, resulting in loss of water and, consequently, death [33, 34]. In addition, these powders may be used in combination with other products, such as vegetable powders to increase the efficacy of pest control.
