2. Biorational insecticides for control sustainability of leaf miner (Liriomyza sativae Blanchard) in chickpea (Cicer arietinum L.)

Keywords: Liriomyza sativae Blanchard, parasitoids, Zabrotes subfasciatus Boheman,

The chickpea crop is the second most important grain of the family Fabaceae grown in Asia, Mediterranean regions, Australia, Canada, USA, and Africa [1]. Globally, the chickpea is planted on an area of nearly 12 million hectares with an approximate production of 11,308,684 tons. This crop develops during the winter under different agroclimatic conditions; its production in Mexico is 271,894 tons annually, of which Sinaloa and Sonora generate 70 and 20%, respectively. Most of it is destined for the international market [2]. Chickpea is an important crop for Sinaloa due to the harvested area, volume, and quality of grain produced over an area of 60,000 hectares,

The study of the biological activity of some compounds present in plants offers an opportunity to discover new and efficient insecticides for pest control [4, 5] which could be tolerated by crops and harmless to consumer; different researches have been observed and reported the insecticidal action of different plant extracts [6–8]. The objective of this research was to determine the efficacy of biorational insecticides to sustainably control the leaf miner (Liriomyza sativae Blanchard) without totally inhibiting the presence of the parasitoids of this pest in

On the other hand, beans is one of the most sown and consumed legumes in Mexico. During the 2014–2015 agricultural cycle, 220,263 ha was sown at the state of Sinaloa, 58,550 ha, to be placed in the first place in terms of sowing and harvesting of this grain [9]. Bean is one of the essential foods for the world population, which makes necessary the conservation and protection of this grain against various factors that affect it, within these stands the importance of the Mexican weevil (Zabrotes subfasciatus Boheman, Coleoptera: Bruchidae) of the bean. The larva feeds on grain and causes severe damage and decreases the germinative power of the seed, by considerably damaging the cotyledons, on which the damages by oviposition and the perfora-

Storage pests are one of the most important problems in storage of grains and seeds, if they are not controlled in a timely manner, and cause direct damages that affect the conservation of the grain. Likewise, they cause damages indirectly when they are invaded by various microorganisms such as fungi and bacteria that contaminate them, which can cause problems in humans when consumed. There are few products that can be used reliably for stored grains for pest control, mainly insecticides and fumigants that are not very persistent in Mexico and in the world, which makes it necessary to seek more alternatives to reduce the damages that cause the pests of stored grains, which do not affect the environment and human health. At the global level, different alternatives for the control of storage pests have been tested. These include treatments based on heat and cold; the use of plant extracts and mineral substances; pheromones; biological control; and the use of chemicals that are preferably under residual

tions that are the feeding chambers of these insects can be observed [10, 11].

power and do not cause effects on grains, seeds, and consumers [12–15].

chickpea, beans

2 Insecticides - Agriculture and Toxicology

with an average yield of 1.7 tons per hectare [3].

1. Introduction

chickpea cultivation.

The research on Liriomyza sativae Blanchard was performed by two experiments that were established in the experimental field of the Faculty of Agronomy of the Autonomous University of Sinaloa, located at 17.5 km of Culiacan-Eldorado road, Culiacan, Sinaloa, Mexico, with coordinates 24� 48<sup>0</sup> 30<sup>00</sup> N, 107� 24<sup>0</sup> 30<sup>00</sup> W and 38.54 m. The climate of this region is very warm to semidry. Average annual rainfall varies from 500 to 700 mm. The average annual maximum temperature is 25�C. The soils of this region are predominantly clayey [16].

The experiment design was randomized complete blocks with four replicates, where the experimental plot consisted of six furrows of 10 m long with 0.8 m distance from each other. The useful plot was the two central grooves minus 1 m from each end. The first planting took place on December 21, 2012 and the second planting on December 30, 2013, both manually with a density of 15 plants per linear meter. Five treatments were evaluated: three biorational insecticides: chlorantraniliprole + ethoxylated alkyl aryl phosphate ester (100 mL + 1.0 L ha�<sup>1</sup> ), cyromazine + Bacillus thuringiensis (80 g + 1 kg ha�<sup>1</sup> ), spinosad + sugar (416.6 mL + 2.08 kg ha�<sup>1</sup> ), cyromazine + Bacillus thuringiensis (80 g + 1 kg ha�<sup>1</sup> ), spinosad + sugar (416.6 mL + 2.08 kg ha�<sup>1</sup> ); one conventional insecticide chlorpyrifos + ester ethoxylate alkyl aryl phosphate (1.5 L + 1.0 L ha�<sup>1</sup> ); and absolute control (without application of insecticides), applying them on the foliage twice. This was done in each evaluation year.

Two applications per cycle were performed on February 9 and March 16, 2013; 02 and 23 February, 2014 with a Maruyama motor pump with a capacity of 25 L, an output boom, and cone nozzle TX5, whose water expenditure was 208 L ha�<sup>1</sup> . The insecticides were applied when the population and leaf miner damage exceeded the economic threshold of 20% to the foliage [17].

Samples of live larvae and empty mines were carried out weekly on a leaf of 10 randomly selected plants. Of each useful plot, 100 leaves were collected and confined in 0.5-L plastic containers at room temperature. After 12 days, the adult miners and emerged parasitoids were separated and confined in glass flasks with 70% alcohol. For identification of the miner, the male abdomen was introduced into a 10% potassium hydroxide solution to soak the tissue for 10 minutes at 80�C and then washed with distilled water to remove the potassium hydroxide. With the preparation immersed in 70% alcohol, the cuticle and tissues were separated from the abdomen until the complete genitalia were cleaned and exposed [18]. With the help of codes and schemes of the male genitalia published by Spencer and Stegmaier [19] and Spencer and Steyskal [20] the taxonomic determination was made. Identification of the parasitoids emerged from the leaf samples was carried out using the keys of Wharton [21] for the genus of the Braconidae family, whereas for the genus of the Eulophidae family, the keys of La Salle and Parrella [22].

To determine the percentage of damage, weekly damage and healthy leafs of three plants per repetition were counted, and the percentage of damage was calculated with a three rule simple modified. Harvest was performed when the culture reached its physiological maturity and the data were transformed to be analyzed with the statistical package SAS 9.1 [23] and then this showed significant differences that were submitted to Duncan's multiple range test with α = 0.05 for mean separation.

While in the entomology laboratory of the same, faculty research was done to determine the efficacy of diatomaceous earth doses, where the colony of beans weevil (Zabrotes subfasciatus Boheman) was purified in glass bottles with a capacity of 5 kg, which were kept under a temperature that fluctuated between 30 and 35�C, with a purpose of having a homogeneous colony for the test.

To establish the tests; polystyrene beakers with capacity of 500 g, and 2 kg of bean per treatment were used; the application of the diatomaceous earth was homogenized on the grain, then 20 adults of bean weevil were deposited in each repetition and covered with organza cloth. The investigation was carried out in two phases: (a) the first one was done in a completely random design with seven treatments and four repetitions. The treatments were diatomaceous earth at doses of 1.0, 2.0, 3.0, 4.0, and 5.0 g kg�<sup>1</sup> of seed, a chemical control (deltamethrin) at a dose of 1.0 mL kg�<sup>1</sup> of seed, plus an absolute control (without application of substances); (b) the second phase consisted of another completely random experimental design with the same amount of treatments and repetitions, but with the doses of 0.2, 0.4, 0.6, 0.8, and 1.0 g kg�<sup>1</sup> of diatomaceous earth, a chemical control (deltamethrin) at a dose of 0.1 mL kg�<sup>1</sup> of seed plus the absolute control.

In the both phases of the experiment, the response variables were the percentage of dead adults and the germination of bean seeds. In the first phase, mortality was determined with the number of live and dead insects in each experimental unit, at 15, 30, 45, and 60 days after application (daa), while in the second phase, it was done at 10, 20 30, and 40 daa. With the averages of mortality in each experimental unit, the percentage of effectiveness was obtained by the following Eq. [24]:

$$\text{Corrected mortality} = \frac{\text{(mortality of the treatment-mortality of the absolute control)} \times 100}{100 - \text{mortality of the absolute control}}$$

Based on the final averages of the two experiments (Table 1), it could be interpreted that after applying the biorational insecticides, chlorantraniliprole, cyromazine, and spinosad, twice as well as the conventional insecticide, chlorpyrifos, there was no statistical difference between the efficacy of the biorationals and that of the conventional one, and live larval populations of L. sativae were reduced to 43, 33, 22, and 39%, respectively, compared to the 100% presence of larvae in the foliage on average in the absolute control in the cycle 2013, while in 2014, the respective decreases were 55, 47, 45, and 46%. The tendency of the population of L. sativae to stay below the economic threshold in the two experiments, from the second application, was perhaps due to the physiological maturity of the chickpea approaching the senescence of the

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

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

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Figure 1. Liriomyza Sativae: (A) aedeagus ventral view, (B) aedeagus side view, and (C) sperm pump.

According to the final averages of Table 2, in 2013, the percentage of empty mines was reduced to 29, 37, 11, and 29% with chlorantraniliprole, cyromazine, spinosad, and chlorpyrifos, respectively, compared with 100% represented by the average of the control. In 2014, the respective decreases were 19, 3, 16, and 22% with the same treatments. In addition, the time of action of biorationals was very similar to that of chlorpyrifos. The results allowed to corroborate that the biorationals are products that can be used for the control of L. sativae with

foliage and, consequently, to the harvest grain.

the same effectiveness of the conventional insecticide chlorpyrifos.

Germination was evaluated with 100 bean seeds planted in polystyrene trays filled with peat moss and determined at 10, 20 and 30 daa of the diatomaceous earth and deltamethrin doses, counting the seedlings emerged in each of the experimental units and comparison of averages with respect at average of the absolute control, while percentages were also determined with the equation of Abbott [24]. All data were subjected to an analysis of variance and multiple comparison of means of Tukey test (α = 0.05) of the statistical package SAS 9.1 [23].
