The present study was carried out in El Giza Research Station affiliated to the Agricultural Research Centre (ARC)—Egypt. El Giza Governorate is located on the west bank of the Nile, 4.9 km southwest of central Cairo on 30.01˚N latitudes and 31.21˚E longitude. A soil analysis test was carried out in the Soil, Water and Environment Research Institute, ARC, to identify the soil properties in the experimental area. The analysis showed that the soil is clay with 36.3% clay, 37.6% silt and 26.1% sand. Percentages of organic matter, nitrogen, phosphorus and potassium were 1, 0.003, 0.001 and 0.03, respectively. Soil pH was 7.73 whereas EC, wilting point and field capacity recorded 0.5 ds/m, 20.2% and 43.8%, respectively.

The study extended from November till March, in two successive seasons, 2016/2017 and 2017/2018. Quinoa was sown on 20^th of November of each season. Weather conditions including average temperature, average relative humidity, precipitation and average wind speed were daily recorded with the assistance of colleagues in the Central Laboratory for Agricultural Climate, ARC (Table 1). The climate is arid, characterized by no precipitation during the experiment period, relative humidity was moderate most of the time and wind speed was light as it did not exceed 0.8 m/sec.

Two types of fertilizers were used, i.e. compost and vermicompost made up of plant wastes and cattle manure (in case of vermicompost the earth worm Eisenia foetida was used). Both fertilizers were provided by the Central Laboratory of Organic Agriculture (CLOA), ARC. Compost and vermicompost were incorporated in the soil before sowing quinoa at rates of 5 and 4 m³/feddan, respectively (1 feddan = 0.42 hectare). Table 2 and Table 3 present the compost and vermicompost analyses that were carried out in CLOA.

Treatments were arranged in a complete randomized block design. There were

Ws = Weed seeds, Nem. Nematodes.

Ws = Weed seeds, Nem. Nematodes.

three replicates for each treatment, i.e. compost, vermicompost, and untreated control. Each plot had an area of 21 m² and consisted of 10 rows, every row measured 6 m long and 3.5 m width. Space between rows was adjusted to 60 cm; whereas, within-row spacing between plants was 20 cm. Quinoa grains, variety Masr 1, were provided by the Department of Maize and Sugar Crops, Plant Pathology Research Institute, ARC. After one month of cultivation quinoa plants were thinned to 2 plants per hill. All agronomic practices were maintained constantly when required. Manual weed control was carried out when necessary and quinoa was irrigated monthly during the whole season (4 irrigations). No fungicide or pesticide treatments were applied.

1) Pests, parasitoids and predators incidence

Yellow sticky traps measuring 45 × 25 cm were used to detect insects’ numbers attracted to quinoa crop under field conditions. Using sticky traps was encouraged by the low wind speed recorded during the experimental period as mention in Table 1. Four traps were used in each plot including the control plot. Three weeks post cultivation traps were hanged with the help of wooden stakes 30 cm above the top of the plants reversing wind direction. Traps were adjusted vertically whenever the crop attained additional growth and they were inspected every two weeks on a regular basis. Upon the collection of the sticky traps, they were wrapped with clear plastic cling film for protection, transferred to the laboratory for sorting, identifying and counting. The identification and counting of insects on the traps was carried out in the Plant Protection Research Institute, ARC. Meanwhile traps were replaced with new ones after each inspection date.

2) Grain yield measurements

Quinoa grains were harvested when about 95% of the plants reached maturation phase. Ten plants were randomly chosen from each plot, bulked and weighted. Grain yield/plot was measured and converted to Kg/ ha. In addition, a sample of 1000 seeds from the bulked seeds of each plot was weighed.

Data were subjected to one way Analysis of Variance (ANOVA) and the treatment means were statistically differentiated by performing Least Square Means test (LSD) at p < 0.05 level using SPSS software.

Upon the collection of the sticky traps, they were transferred to the laboratory for identification. Table 4 presents the insects pests, parasitoids and predators found on the sticky traps.

1) Aphis craccivora

The black legume aphid was one of the pests found in large numbers on the yellow sticky traps in quinoa field. Aphids’ numbers fluctuated from December to March during the two seasons of the experiment in all the treatments, as illustrated in Figure 1. Aphids had two peaks (on January 23^rd and March 7^th). Mean number of aphids’ population ± SD in compost, vermicompost and control treatments during the month of December were 29.7 ± 4, 57.7 ± 4.1 and 68.3 ± 4.2, respectively. One-Way ANOVA showed that there was a high significant difference between aphids mean numbers in the three treatments (p = 0.002). During the month of January aphids’ population mean numbers in all treatments decreased and then increased again. In compost treatment, 9^th of January, it reached 14.3 ± 3, whereas, vermicompost and control treatments recorded 22.3 ± 2.5 and 37.3 ± 3, respectively. Results proved that there was a high significant difference between all the treatments, where p < 0.001. Two weeks later, on the 23^rd of the same month, mean numbers increased to reach 165 ± 65, 296 ± 55 and 232.3 ± 3 in the three treatments, respectively, with a significant difference between treatments (p = 0.047).

February population, on the other hand, showed a slightly different trend in pest mean numbers where they decreased during the two periods of data collection. In compost treatments during the 7^th and 21^st of February, mean numbers of aphids recorded 149.7 ± 8.9 and 78 ± 3. Vermicompost recorded 177 ± 9 and 92 ± 3.2, whereas, aphids in control plots reached 182 ± 9.1 and 107.3 ± 3 in the two periods, respectively. Moreover, mean numbers continued to fluctuate again during the month of March where pest population increased on the 7^th of March, then decreased on the 21^st of March, as illustrated in Figure 1.

2) Empoasca decipiens

The potato leafhopper, Empoasca decipiens, did not appear in quinoa field till the last week of January, where its mean number in compost plot recorded 5.3 ± 1.8 and increased in vermicompost and control treatments to reach 20 ± 2 and 25 ± 1, respectively. ANOVA test showed that there was a high significant

difference between treatments where p = 0.001. During the month of February, on the 7^th, population of E. decipiens increased to reach 17.7 ± 4, 26.7 ± 3.8 and 37 ± 3.84 in compost, vermicompost and control treatments, respectively. Two weeks later the numbers increased up to 42.3 ± 3.6, 41.7 ± 4 and 68 ± 3.61, in the three treatments, respectively. High significant differences were noticed in both dates, where on the 7^th of February p < 0.001 and on the 21^st no significant differences were found between compost and vermicompost (p = 0.3) whereas, control results and both fertilizers showed high significant differences as p = 0.003. Only one peak occurred during quinoa growth which was on the 7^th of March where numbers of E. decipiens increased as illustrated in Figure 2, while on the 21^st of March mean numbers of the pest decreased again till it reached 33 ± 1.6, 20 ± 2 and 37.6 ± 1.61, in compost, vermicompost and control treatments, respectively, with high significant differences between all treatments (p ≤ 0.001).

3) Bemisia tabaci

Whiteflies appeared early in quinoa crop (in December) where mean numbers of the pest on the yellow traps recorded zero, 5.3 ± 1.5 and 8.3 ± 0.5, in compost, vermicompost and control plots, respectively, with High significant differences between the three treatments, where p < 0.001. As shown in Figure 3, data

collection after two weeks showed that B. tabaci disappeared from the field completely and then after another 14 days it appeared again recording mean numbers of 12.3 ± 2.5, 29 ± 3.6 and 28.3 ± 3 in compost, vermicompost and control plots, respectively, and this date (Jan. 23^rd) represents the first peak of the pest population. High significant differences were noticed between compost on one hand and vermicompost and control on the other hand, where p < 0.001, while no significant differences appeared between control treatment and vermicompost (p = 0.7).

On February 7^th mean numbers of the pest decreased to 3.3 ± 1.2, 8.3 ± 1.5 and 20.3 ± 1.6 in the three treatments, respectively. Mean number of whiteflies did not increase significantly when results were recorded 14 days later, whereas on the 7^th of March pest’s mean number increased up to 13.7 ± 2, 31.3 ± 2.2 and 30.7 ± 2.5 in compost, vermicompost and control treatments, respectively, showing the second peak of the pest population. One way ANOVE test revealed high significant differences between quinoa fertilized with compost and quinoa in control and vermicompost plots where p < 0.001. Whereas, both vermicompost and control plots did not show any significant differences as p = 0.8. Finally, on the 21^st of March numbers of the pest declined again to reach 11.6 ± 2.1, 17 ± 3.6 and 20.3 ± 1.5, respectively.

Two types of predators were detected in quinoa field, i.e. the green lacewing Chrysoperla carnea and the ladybugs Coccinella vicina and Coccinella septempunctata. Numbers of predators were very low compared to the number of pests, as shown in Figure 4 & Figure 5. During December, the green lacewing appeared in few numbers (0.7 ± 1.1, 1.7 ± 1.5 and 2.7 ± 0.6). One way ANOVA test showed significant differences between compost and both vermicompost and control as p = 0.1. There was no significant difference between vermicompost and the control treatments (p = 0.005). On the other hand, the ladybugs did not appear till the 9^th of January. The Coccinella spp. recorded 2 ± 1, 6 ± 0.6 and 5.3 ± 1.5 in the three treatments, respectively. Mean numbers of C. carnea on the 9^th of January were 0.7 ± 1.1, 3 ± 1 and 4.7 ± 1.1 in compost, vermicompost and control plots, respectively.

Two weeks later, no ladybug individuals were found on the yellow sticky traps, whereas the green lacewing recorded mean numbers of 3 ± 1.7, 5 ± 1 and 12 ± 1.5, in the three treatments, respectively. One way ANOVA showed significant differences between all treatments (p ≤ 0.001). Both predators disappeared again during the next two weeks and started to reappear on the 21^st of February. C. carnea recorded 0, 4.3 ± 1 and 5.3 ± 2, whereas Coccinella spp. mean numbers increased up to 4 ± 1, 10 ± 0.9 and 2.7 ± 1.1, in the three treatments, respectively (as illustrated in Figure 4). Mean numbers of C. carnea increased again to reach 8 ± 1.5, 14 ± 1 and 17 ± 1.2 in compost, vermicompost and control plots, respectively. On the 21^st of March, all treatments recorded zero number for this predator.

On the other hand, results of the ladybug on the two data collection dates of March were closed to each other, as shown in Figure 5.

All the parasitoids detected in quinoa fields were aphid’s parasitoids, i.e. the green bug aphid’s parasitoids (Lysiphebus fabarum, Lysiphebus testacoipes), Bracon sp. and Trioxys sp. Those parasitoids appeared in quinoa field on the 23^rd of December recording mean numbers of 14 ± 1.7, 20.8 ± 2 and 30.6 ± 3.7 in compost, vermicompost and control plots, respectively. High significant differences appeared by ANOVA test as p ≤ 0.001. Mean numbers decreased when data were collected 14 days later as shown in Figure 6 and then increased again on the 23^rd of January to reach 38 ± 5.2, 73.3 ± 15.2 and 74.3 ± 4 in the three treatments, respectively. During the next two dates of data collection mean numbers of the parasitoids continued to decrease as shown in Figure 6, then numbers increased on the 7^th of March to record 18 ± 5, 9 ± 1 and 30.3 ± 2.5, respectively. One way ANOVA analysis proved significant differences between treatments as p ≤ 0.001. By the end of March parasitoids mean number decreased again to reach 3.3 ± 1.5, 4 ± 1 and 5 ± 1, respectively. No significant difference was recorded as p = 0.3.

Results showed that the yellow sticky traps in the plots fertilized with compost caught the least numbers of insects during the two seasons. As shown in Figure 7, in compost plot the total average mean numbers of aphids were 110 while both vermicompost and control average mean numbers were 160 and 166, respectively. Leafhoppers, on the other hand, recorded its highest number in the control plot (35) while the least number was recorded in the compost treatment, i.e. 23. Although B. tabaci was less in its number compared to the other two pests, still, its number in compost was less than those in vermicompost and control treatments as shown in the same figure.

Numbers of predators in the field were not high compared to the parasitoids where total average number of parasitoids was 12, 19 and 25 in compost, vermicompost and control treatments whereas predators numbers did not exceed 6 individuals in their highest presence as shown in Figure 7.

Fertilization, either vermicompost or compost, had a positive effect on quinoa yield/plant compared to control plot. The analysis of variance of data revealed high significant differentiation between both fertilizers and the control treatment (p = 0.4) whereas no significant difference was noticed between the two fertilizers. Both fertilizers resulted in seed yield of 27 ± 1.9 and 26.4 ± 1 gm. plant, respectively, whereas control plants gave yield of 23.6 ± 1.4 gm. plant, as shown in Figure 8(a).

Further, 1000 seeds weight reached in case of vermicompost plots 467.4 ± 39 gm. while control treatment gave the least weight, i.e. 363.25 ± 41 gm. and compost fertilized plants gave 1000 seeds weight of 353 ± 30 gm. as illustrated in Figure 8(b). Significant differences were noticed between all treatments, yet, it was higher between vermicompost and both control and compost treatments, i.e. p < 0.001.

On the other hand, vermicompost showed higher yield values per ha compared to both compost and control plots, i.e. 843 ± 90, 801 ± 92 and 771 ± 92 Kg/ha, respectively (Figure 8(c)). Data analysis proved there were high significant

differences between vermicompost yield and both control and compost (p = 0.86), whereas compost and control plots showed no significant differences (p < 0.001).

Reaching high yielding production occurs through good nutrition management. Several researchers discussed the importance of organic fertilization in improving plant health. Organic fertilization keeps soil moisture as organic matter improves soil water-holding capacity and increases water and nutrients availability for plants which in return gives strong and healthy crops with high production rates and less pests’ infestation, something that is not provided by synthetic fertilization [25] [26]. Crops grown in organic fertilized area harbor less number of insect pests [27]. Moreover, organic fertilizers found to be more effective than chemical fertilizers in inducing rice growth and its tolerance to insect pests and diseases [28]. Application of organic fertilizers was sound effect to protect natural enemies under field condition. Shifting from organic to chemical soil management increased the potential of certain insects and diseases to cause economic losses [29].

Egypt has huge wheat gap, as the total production of wheat grains covers only 55% of the Egyptian needs and therefore, it is extremely necessary to search for suitable alternatives that could be integrated in making wheat flour bread to overcome the wheat gap and satisfy consumers’ needs [30]. Quinoa flour can partly replace wheat flour in baked products [31]. Besides, quinoa is a drought-tolerant crop that resists adverse conditions, has a high nutritive value and is able to adapt different ecological environments and climates [32]. Further, quinoa has the highest income and is the most profitable compared to other grain crops such as wheat, soybean and canola [12].

Considering the above mentioned issues and as quinoa is a new crop in Egypt, more efforts are needed to raise awareness about all aspects related to quinoa’s cultivation. The current study investigated the effect of compost and vermicompost on quinoa yield, pests’ and natural enemies’ incidence and population dynamics.

No specialized quinoa pests were found, rather, polyphagous pests were detected together with generalized natural enemies. This finding is in accordance with what Rasmussen et al. [16] declared. Few types of pests were found in the current experimental field, i.e. the black legume aphid A. craccivora, the potato leafhopper E. decipiens and the whitefly B. tabaci.

Several authors mentioned the association of Aphis spp. in quinoa fields, i.e. [33] [34] [35]. Additionally, Aphis was stated as an important quinoa pest in Europe [16]. Nampeera et al. [36] mentioned that 87% of their survey respondents, in Kenya, determined aphids as a major pest attacking amaranths spp. and 96.8% ranked them as number-one insect pest. They also declared whiteflies as one of the pests attacking amaranths and causing damage. Quinoa shoots were also found to be attacked by sapsuckers (Aphididae and Cicadellidae) [37]. On the other hand, leafhoppers were declared as one of the pests attacking quinoa crop [16]. This data resembles the results obtained in the current study as these three pests were detected in the experimental area and aphids were the most abundant pest compared to the other two pests, i.e. whiteflies and leafhoppers.

It was noticed that aphids peaked twice during quinoa growth season, i.e. 23^rd of January and 7^th of March; these results are in conformity with Ya' bar et al. [37] who revealed that Aphididae had two peaks, at the beginning and end of quinoa growth season.

It is noteworthy that the present investigation provides basic information on seasonal incidence of whitefly on quinoa crop, as no data was found in the literature concerning this issue; rather the pest population was studied on many other crops. In the current study whiteflies peaked two times, i.e. 23^rd January and 7^th March (the same dates of aphids peaks). This confirms the findings of Yadav et al. [38] and Swathi [39] who declared that whiteflies peaked two times also but during tomato, soybean and green gram growth seasons in India. It seems that the pest behaves the same way in quinoa cultivation as demonstrated by the current findings.

The present study is also considered as first attempt that broadens our knowledge on the dynamics of potato leafhoppers on quinoa crop. It was proved that this pest peaked one time only during quinoa growth season; on the 7^th of March. This might be due to the increase in temperature and decrease in the relative humidity (19˚C and 53%) compared to the other months. A similar belief was expressed by Naseri et al. [40] and Rassoulian et al. [41] who said that population density of leafhoppers increased with increasing temperature and decreasing relative humidity on bean and soybean. Yet, other researchers, i.e. [42] [43] stated that E. decipiens peaked two times on kidney bean and some other plantation under Egyptian conditions. Thus, it could be concluded that plant species might have an effect on the population dynamics of E. deipiens.

The current investigation proved that although compost and vermicompost showed direct effect on the mean numbers of pests attacking quinoa crop under the experimental condition, yet, the date each pest peaked did not change from one fertilizer to the other.

Likewise, this research demonstrated that pests found in organic fertilized quinoa plots are low in numbers compared to those in unfertilized plots. Altieri and Clara [29] found similar results and mentioned that crops grown in soils with organic matter exhibit lower abundance of several insect herbivores, reductions that could be attributed to lower nitrogen content in organically farmed crops. They added that quinoa plants fertilized with compost attracted less numbers of pests as proved in the current study. The superior of compost over vermicomopost might be explained according to Saranraj and Stella [44] who said that during preparation of vermicompost it retains more N than the traditional composts, therefore, using vermicompost increases the levels of total nitrogen in the soil and subsequently decreases plant resistance to pests as mentioned above. This interpretation could be applied here, as the parameters and minerals analysis of both compost and vermicompost proved that the percentage of nitrogen in vermicompost is double its percentage in compost, i.e. 1.2 and 2.4%.

Parasitoids and predators were present in quinoa field. Four species of parasitoids were detected, i.e. Lysiphebus fabaru, Lysiphebus testacoipes, Bracon sp. and Trioxys sp. whereas, predators were represented by the existence of two families, i.e. family Chrysopidae: Chrysoperla carnea and family Coccinellidae: Coccinella vicina and Coccinella septempunctata. It was noticed that parasitoids peaked two times; January, 23^rd and March, 7^th which happened to be the same peak dates of aphids, grasshoppers and whiteflies. On the other hand, although predators were few in numbers; they peaked twice as well. Results verified that parasitoids appeared much earlier than predators and their mean numbers in the field were higher than predators in all treatments, although their numbers were less in compost treatments than both vermicompost and control plots; that might be attributed to the decrease in pests’ numbers in compost treatments. The superiority of parasitoids over predators in the current investigation might be assigned to their early appearance in the field which allowed their early parasitism that led to reduction in predation rate and consequently predators’ numbers. This explanation is supported by the findings of Tan et al. [45] who justified that the predator Harmonia axyridis of the family Coccinellida exhibited the lowest rates of predation when released in the presence of whitefly specific parasitoids (Encarsia formosa and Encarsia sophia) and showed a significant preference for non-parasitized nymphs as prey. Further research work is needed to prove this explanation. Reduction in predators number might also be attributed to the prevailed temperature during the current experiment which was 14.7˚C, 14˚C and 16.1˚C during December, January and February, respectively, and which is not favorite for the development of coccinellidae individuals as proved by Katsarou et al. [46] who stated that mortality of immature stages of these predators was the highest at the temperature of 14˚C whereas egg and larval mortality exceeded 80% at 17˚C and 18˚C. The same verification could be applied to C. carnea as low temperature causes high mortalities among the predator individuals and the suitable development temperature ranges from 25˚C to 31˚C [47]. Costa and Stary [48] proved that L. testaceipes follows its host aphids apparently in all environments and its occurrence covers most of the season.

Results showed that using compost and vermicompost enhanced crop yield (seeds/plant, weight of 1000 seeds and yield/ha). Yet, vermicompost resulted in more yield when compared to compost and control. These results are in accordance with many researchers; Islam et al. [23] demonstrated that vermicompost application showed higher result for growth, yield indices and nutrient content of Amaranthus viridis compared to conventional aerobic compost and therefore, they recommended farmers to use vermicompost in crop production. Edwards et al. [49] reported that vermicompost has a much finer structure than compost and there is a considerable difference in their performances and effects on plant growth. In addition, Saranraj and Stella [44] stated that vermicompost plays a major role in crops growth and yield.