## 4 Discussion  
This research reveals the dynamics of the cereal aphid population fed on wheat plants under two different cultivation modes in desert-oasis areas. Most studies show that pest outbreak issues have always combined with ecological habitat exacerbation, particularly when monoculture application grossly oversimplifies the variety of the arthropod community [34; 35]. In supplying this deficiency, intercropping wheat with other crops and fruit trees has been conducted by lowering the densities of pest insects [36]. [PERSON] et al. (2017) found significant differences in the populations of immigrating winged aphids and their natural enemies among different wheat coverage rates, and the reduction in wheat planting proportion showed a negative trend of wheat aphids. The wheat monoculture system was found to have the most wheat aphids [37]. [PERSON] et al. (2011) also observed wheat monoculture's maximum aphid densities compared to the intercropping pattern [38]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Treatments** & **Fields** & **1 DAS Control Effects (\%)** & **3 DAS Control Effects (\%)** & **7 DAS Control Effects (\%)** \\ \hline P3 & & 75.16\% \(\pm\) 0.91\% \({}^{\text{a}}\) & 73.80\% \(\pm\) 3.70\% \({}^{\text{a}}\) & 92.06\% \(\pm\) 1.49\% \({}^{\text{a}}\) \\ P3M & & 82.79\% \(\pm\) 3.41\% \({}^{\text{b}}\) & 80.14\% \(\pm\) 2.74\% \({}^{\text{b}}\) & 92.62\% \(\pm\) 3.45\% \({}^{\text{a}}\) \\ P4 & & 66.03\% \(\pm\) 1.79\% \({}^{\text{c}}\) & 63.53\% \(\pm\) 3.06\% \({}^{\text{c}}\) & 84.29\% \(\pm\) 2.87\% \({}^{\text{b}}\) \\ P4M & XD60 & 69.75\% \(\pm\) 3.92\% \({}^{\text{c}}\) & 66.47\% \(\pm\) 3.03\% \({}^{\text{c}}\) & 86.01\% \(\pm\) 4.03\% \({}^{\text{b}}\) \\ P9 & & 73.80\% \(\pm\) 1.61\% \({}^{\text{a}}\) & 61.76\% \(\pm\) 2.77\% \({}^{\text{c}}\) & 75.72\% \(\pm\) 1.33\% \({}^{\text{a}}\) \\ P9M & & 74.36\% \(\pm\) 3.90\% \({}^{\text{a}}\) & 73.50\% \(\pm\) 3.51\% \({}^{\text{a}}\) & 74.36\% \(\pm\) 3.90\% \({}^{\text{a}}\) \\ P10 & & 62.44\% \(\pm\) 1.75\% \({}^{\text{b}}\) & 53.54\% \(\pm\) 3.32\% \({}^{\text{d}}\) & 71.20\% \(\pm\) 2.31\% \({}^{\text{a}}\) \\ P10M & & 65.13\% \(\pm\) 2.36\% \({}^{\text{b}}\) & 67.48\% \(\pm\) 1.92\% \({}^{\text{b}}\) & 65.139\% \(\pm\) 2.36\% \({}^{\text{b}}\) \\ \hline \hline \end{tabular} Note: The same letter represents no significant difference between different concentrations and application methods of the same chemical agent. Numbers in first column correspond exactly to the serial numbers in Table 1.  
\end{table} 
Table 4: _Cont._The distribution of wheat aphids under walnut-wheat intercropping in southern Xinjiang differed from the studies stated above in other ecological zones. Our result showed that a higher amount of apterous adult aphids exists under a walnut-wheat intercropping pattern for three consecutive years. This could be due to the inevitable decrease in some growth indicators such as root length density, leaf area index, and light use efficiency of wheat plants resulting from the intense belowground and aboveground competition for resources [39, 40, 41, 42, 43, 44]. These indicators could characterize the capability of photosynthesis and nutrition status of wheat plants, leading to a severe yield depression of intercropped wheat crops [45]. Some previous studies showed that host plant quality affects herbivorous insect fertility at the individual and population levels [46]. Poor food quality could lead to a higher survival rate, a shorter development period of _Drosophila melanogaster_[47], a smaller body size of _Aphis glycines_[48], and the maximum aphid abundance of _M. dirhodum_[49]. The poor nitrogen condition of the host plant can increase the population of _Schiazphis graminum_ by shorting the reproductive period [50]. The male cystamore aphid, _Drepanosiphum plantonidis_, fed on poor-quality host plants, takes longer to appear than it would under ideal nutritional conditions. The female bias in sex ratio and competition alleviation is proven due to the host's poor quality [51, 52].