# Research on Plant Disease and Pest Diagnosis Model Based on Generalized Stochastic Petri Net
## 2 Early Warning System for Plant Pests and Diseases
### Influence of Environmental Factors
By scientifically regulating these environmental parameters, the reproduction and spread of pests can be effectively suppressed, thereby ensuring the healthy growth of plants. The pest dynamics model can be expressed sequentially as  
\[\text{D}_{41} =\text{f}(\text{E}_{3},\text{ A}_{1},\text{ TR}_{2},\text{ H}_{1},\text{ L}_{1},\text{ PH}_{3}) \tag{5}\] \[\text{D}_{51} =\text{f}(\text{E}_{2},\text{ A}_{1},\text{ TR}_{3},\text{ H}_{1},\text{ L}_{1},\text{ PH}_{2})\] (6) \[\text{D}_{61} =\text{f}(\text{E}_{2},\text{ A}_{1},\text{ TR}_{1},\text{ H}_{3},\text{ L}_{1},\text{ PH}_{2})\] (7) \[\ldots\] \[\text{D}_{\text{n1}} =\text{f}(\text{E}_{\text{a}},\text{ A}_{\text{b}},\text{ TR}_{\text{c}},\text{ H}_{\text{d}},\text{ L}_{\text{e}},\text{ PH}_{\text{f}}) \tag{8}\]  
In practical planting, a plant species is often simultaneously affected by multiple pests and diseases. Different pests and diseases tend to coexist under similar or complementary environmental conditions, resulting in cumulative effects on the plants. Therefore, comprehensively considering and regulating these environmental conditions is an important strategy to prevent the outbreak of multiple pests and diseases. The following formula represents the influence of multiple pests and diseases on the plant P\({}_{\text{s}}\):  
\[\text{D}_{21} =\text{f}(\text{E}_{1},\text{ A}_{1},\text{ TR}_{2},\text{ H}_{1},\text{ L}_{1},\text{ PH}_{1}) \tag{2}\]0 \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline C & Disease & C & Maintenance & C & fertilizer & C & Temperature & C & humidity & C & Light & C & PII Value \\ \hline \multirow{2}{*}{D1} & \multirow{2}{*}{Aghids} & \multirow{2}{*}{E1} & \multirow{2}{*}{Dxy} & \multirow{2}{*}{A1} & \multirow{2}{*}{Dxy} & \multirow{2}{*}{A2} & \multirow{2}{*}{T2A} & \multirow{2}{*}{15-20 \({}^{\circ}\)C} & \multirow{2}{*}{H1} & \multirow{2}{*}{High} & \multirow{2}{*}{L1} & \multirow{2}{*}{Low Light} & \multirow{2}{*}{PH1} & \multirow{2}{*}{Asholine} \\  & & & & & & & & & & & & & \\  & & & & & & & & & & & & & \\ \hline \multirow{2}{*}{DS} & \multirow{2}{*}{Bours} & \multirow{2}{*}{E2} & \multirow{2}{*}{Inefficient} & \multirow{2}{*}{A2} & \multirow{2}{*}{T2A} & \multirow{2}{*}{20-25 \({}^{\circ}\)C} & \multirow{2}{*}{H2} & \multirow{2}{*}{Moneture} & \multirow{2}{*}{L2} & \multirow{2}{*}{Medicine} & \multirow{2}{*}{H2} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} \\  & & & & & & & & & & & & & \\  & & & & & & & & & & & & & \\ \hline \multirow{2}{*}{Dix} & \multirow{2}{*}{Bix} & \multirow{2}{*}{E3} & \multirow{2}{*}{Water Enuma} & \multirow{2}{*}{A3} & \multirow{2}{*}{TWater Enuma} & \multirow{2}{*}{A3} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} \\  & & & & & & & & & & & & & \\  & & & & & & & & & & & & & \\ \hline \multirow{2}{*}{Dix} & \multirow{2}{*}{Discover En} & \multirow{2}{*}{Eix} & \multirow{2}{*}{Aix} & \multirow{2}{*}{Aix} & \multirow{2}{*}{Aix} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} & \multirow{2}{*}{T2A} \\  & & & & & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Classification and definition of environmental factors for pests. where each pest or disease \(\rm D_{i1}\) is a function of the environmental factors (Moisture \(\rm E_{a}\), Fertilizer \(\rm A_{b}\), Temperature \(\rm TR_{c}\), Humidity \(\rm H_{d}\), Light \(\rm L_{e}\), and PH value \(\rm PH_{f}\)):  
\[\rm D_{i1}=f(E_{a},A_{b},TR_{c},H_{d},L_{e},PH_{f}) \tag{10}\]  
For example, flower \(\rm P_{1}\) is more likely to develop downy mildew, powdery mildew, and aphids in a high-humidity environment.