https://jcp.modares.ac.ir/ Journal of Crop Protection en daily 1 Thu, 01 Oct 2026 00:00:00 +0330 Thu, 01 Oct 2026 00:00:00 +0330 https://jcp.modares.ac.ir/article_29434.html Intercropping is a sustainable agricultural system that resembles natural ecosystems. Biodiversity plays a vital role in the sustainability of intercropping systems. This study aimed to evaluate carabid beetle biodiversity in different safflower/chickpea intercropping patterns. The experiment was conducted in a randomized complete block design with 11 treatments and 3 replications at the research field of Kurdistan University. Experimental treatments included safflower sole cropping, chickpea sole cropping, a replacement series (4:4, 2:2, 1:1, 3:1, and 1:3), and an additive series (20% and 40% chickpea in two Situations: between and around safflower rows). In total, 16 Carabidae predator species were collected from Pitfall traps across the culture patterns, with Curtonotus aulicus being the most abundant. The results showed that intercropping significantly influenced Carabidae abundance. Rarefaction curves indicated that, for an equal number of sampled individuals, cropping patterns 1:3, 3:1, and 40%I had the highest Carabidae diversity, while 40%II and 4:4 had the lowest. Additionally, according to the Bray-Curtis similarity index, sole chickpea cultivation and the 1:1 pattern (76.19%), followed by the 3:1 and 40%I patterns (74.19%), showed the highest similarity in species diversity. Overall, the number of Carabidae species across all intercropping patterns was higher than in sole safflower, indicating a positive response of the Carabidae natural predator population to plant species diversity. However, Carabidae species responded differently to the various intercropping patterns in terms of diversity, richness, and abundance. https://jcp.modares.ac.ir/article_29435.html The insecticidal effects of Conventional Ethanolic Extract (CEE) from five growth stages of Melia azedarach (including flower, small green fruit, big green fruit, ripe fruit, and leaf) on nymphs of Aphis fabae were investigated. In 1-2 day-old nymphs, no significant differences in mortality rates among the extracts were found, with the leaf extract showing the highest mortality rate of 65.24 ± 5.89%. In 3-4-day-old nymphs, the ripe fruit extract had the highest mortality rate at 88.5 ± 2.79%, while the small green fruit extract had the lowest at 31.83 ± 4.17%. Additionally, the insecticidal effects of ethanolic extracts from the five growth stages of M. azedarach were tested using Ultrasound-Assisted Extraction (UAE). For 1-2-day-old nymphs, significant differences were noted between the control and ethanol treatments (P ≥ 0.0001), with lower mortality than the extracts (P ≥ 0.00001). The leaf extract recorded the highest mortality rate (98.0 ± 1.33%), while the big green fruit extract had the lowest (87.5 ± 4.61%). In 3-4 day-old nymphs, the results mirrored previous findings, showing significant differences (P ≥ 0.0001) with higher mortality rates from the extracts (P ≥ 0.00001). Again, the leaf extract had the highest efficacy (96.9 ± 1.30%), while the small green fruit extract had the lowest (86.8 ± 4.72%). When comparing the insecticidal effects of ethanolic extracts obtained through CEE and UAE on A. fabae, the data showed that, except in two cases, UAE significantly increased mortality rates compared with CEE (P ≥ 0.0001). https://jcp.modares.ac.ir/article_29436.html The common sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is a major pest of wheat and barley in Iran. Egg parasitoids (Hymenoptera: Scelionidae and Encyrtidae) represent the most promising natural enemies of this pest. However, these parasitoids often experience host absence early in the season. This study evaluated the effects of different host-deprivation intervals on Ooencyrtus fecundus Ferrière and Voegele (Hymenoptera: Encyrtidae), a widespread egg parasitoid of E. integriceps. Experiments were conducted under constant environmental conditions (25 ± 1 °C, 50 ± 10% RH, and a 16L:8D h photoperiod) with five host-access regimes: continuous access (control), access every other day, every third day, once per week, and full access following a seven-day deprivation period. Parasitism rate decreased as the deprivation interval increased, with the strongest negative effects observed in the once-per-week treatment. Partial compensation occurred during host-access days across all treatments. Females showed substantial recovery when given unlimited access following a long deprivation. Thus, early-season host delays are unlikely to threaten the biological control of the common sunn pest, as O. fecundus can compensate for lost opportunities during subsequent access. Nonetheless, intermittent host availability may negatively affect parasitoid performance. https://jcp.modares.ac.ir/article_29485.html Fig inflorescence nematode, Schistonchus caprifici (Gasperrini, 1864), is a damaging agent in fig orchards of Fars Province. In this study, geostatistical methods were used to determine the geographic distribution and identify critical hotspots, which is essential for designing optimized control strategies. During 2022–2023, a total of 175 samples of profichi syconia (early, mid-, and late-ripening) were collected from Estahban, Khafr, Sarvestan, Kavar, and Shiraz Counties in Fars Province, southern Iran. Nematode extraction and estimation of its population density were done according to the routine procedure in nematology; geostatistical methods were used to simulate the spatial distributions of the fig nematode. Of the total 175 samples of caprifig inflorescence, 138 (78.85%) were infested with the fig inflorescence nematode, S. caprifici, with an average population of 1078.46 nematodes per gram of fig fruit tissue. The average population density of this nematode per gram of caprifig tissue, based on the Kriging method, variogram model, and focusing on high-risk and high-density areas, was 3700 to 4100 in Estahban County, 2000 to 3000 in Khafr County, and 1000 to 1500 nematodes per gram of caprifig fruit tissue in Sarvestan and Shiraz Counties, and less than 1000 nematodes in Kavar County samples. The effective range was three meters in Estahban (small, dense clusters), five meters in Khafr (moderate dispersion), and 7 meters in Sarvestan, Shiraz, and Kavar Counties (low dispersion). The kriging method successfully predicted nematode distribution patterns in this study, which could be an effective tool for designing fig inflorescence nematode management strategies. https://jcp.modares.ac.ir/article_29486.html The allelopathic activity of different Mucuna pruriens (L.) DC. varieties hold considerable potential for developing bioherbicidal cover crops. This study assessed varietal differences in the allelopathic potential of two M. pruriens varieties on rice, Oryza sativa L., and maize, Zea mays L. A Petri dish bioassay was performed using aqueous extracts from dried tissues of each variety, and the L-DOPA content of various plant parts was quantified by HPLC. Although seed germination was less sensitive to allelopathic effects, seedling growth showed dose-dependent inhibition, with root growth more strongly affected than shoot growth. A significant inter-varietal difference in L-DOPA content was recorded; both varieties demonstrated strong allelopathic effects. Notably, leaf extracts—despite having the lowest L-DOPA levels—exhibited the highest inhibitory activity. These findings suggest that the allelopathic effects of M. pruriens are not solely mediated by L-DOPA, contradicting the earlier hypothesis. Instead, other factors, such as plant organ type and extract concentration, strongly influence them. https://jcp.modares.ac.ir/article_29487.html The bird cherry-oat aphid, Rhopalosiphum padi L. (Hemiptera: Aphididae), is one of the most important biotic constraints for corn production. Significant yield loss can occur without pest monitoring and timely management. Understanding the spatial distribution of R. padi is critical to developing a reliable sampling plan. This study aims to characterize the spatial distribution of aphids in corn fields in Karaj (Alborz province, Iran). Field sampling of R. padi populations (nymphs and adults) on corn in Karaj in September 2022 produced a dataset of 20 estimates of mean aphid density (m; number of aphids per plant) and variance (s2). To determine its distribution and inform population density sampling, we investigated the spatial distribution of R. padi using Taylor’s power law and Iwao’s mean crowding. Both methods indicated an aggregated distribution, as the aggregation parameter (b = 1.379) and density contagiousness coefficient (β = 3.577) exceeded 1. We then estimated the optimal sample size (n) at 0.10 and 0.25 precision levels using both models. Optimal sample size decreased with decreased precision and mean aphid density, varying significantly with both the precision level and regression model. At a 25% precision level, the required sample size ranged from 56 to 516 plants (Taylor’s) and from 59 to 802 plants (Iwao’s). When precision is increased to 10%, the required sample sizes become 334–3,227 plants (Taylor’s method) and 371–5,013 plants (Iwao’s method). These data on spatial distribution and optimal sample size are crucial for monitoring and managing R. padi effectively.