Spatial distribution and fluctuating populations of predatory mites (Mesostigmata: Phytoseiidae), phytophagous mites (Acari: Eriophyidae, Tetranychidae) and their relationships with wild chili pepper phenological stages in two Natural Protected Areas of Mexico

Ecological interactions between mites (predatory and phytophagous) and wild plants growing in undisturbed environments play a crucial role to understand their natural settlement, development and dispersion patterns. Pequin chili pepper, Capsicum annuum L. var. glabriusculum, is a low-cost natural resource for local communities living inside Natural Protected Areas (ANP) of Tamaulipas State in Mexico. The aims of this research work were: 1) determine the spatial distribution pattern of predatory and phytophagous mites, 2) determine the spatiotemporal association between predatory and phytophagous mites, and 3) determine the association among different mite species and some phenological stages of Pequin chili pepper. The most abundant phytophagous mites were Tetranychus merganser and Aculops lycpoersici, and the predatory species were Amblyseius similoides, Euseius mesembrinus and Metaseiulus (Metaseiulus) negundinis. Most mite species showed an aggregated distribution pattern according to the plant phenological stages. However, the distribution of mite species throughout time showed different types of aggregation. On the other hand, we found positive associations among A. lycopersici and T. merganser phytophagous mites with A. similoides, E. mesembrinus and M. (M.) negundinis predators mites. The association between plants and mite species were influenced by the phenological stages of Pequin chili pepper. This is an indication of the complexity among trophic-chain interactions that depend largely on the available resources and competition. These two factors serve as foundations for settlement, development and dispersion patterns of certain species.

Biocontrol of Anthracnose Disease on Chili Pepper Using a Formulation Containing Paenibacillus polymyxa C1

Anthracnose disease on chili pepper has been known to seriously interfere with the plant growth and obviously reduce the yield. The disease is caused by Colletotrichum spp. In Bali, Indonesia, six species of Colletotrichum have been identified: Colletotrichum scovillei, C. acutatum, C. nymphaeae, C. gloeosporioides, C. truncatum, and C. fructicola. However, among them the C. scovillei was found to be the most prevalent cause of anthracnose on chili pepper in Bali. Two species of antagonist against C. scovillei, namely Paenibacillus polymyxa C1 and Bacillus siamensis C7B, have been identified. In this study the effectiveness of P. polymyxa C1 formulation was evaluated under greenhouse condition on chili pepper cultivars Cabe Besar. Application of formulation was conducted by a mini hand sprayer once to five times with a week interval. Results of the study showed that treatment with five applications significantly (p < 0.05) reduced the disease incidence, disease intensity, and the yield loss of chili pepper cultivar Cabe Besar. Alose relationship was observed between the number of applications with disease intensity, with coefficient of determination (R2) at 0.929. These results revealed that the formulation of P. polymyxa C1 effectively control the anthracnose disease on chili pepper, particularly on chili pepper cultivar Cabe Besar, and thus can be recommended for field testing to confirm its stability under field conditions.

Chili pepper genotypes assay approach for resistance to Aphis gossypii (Hemiptera: Aphididae)

The cotton aphid (Aphis gossypii), is one of the most devastating insect pests for chili pepper that damages the crop and transmits several viruses. Thus far, there is no commercial chili cultivar with effective resistance to cotton aphids (CA). The present study aimed to develop a reliable and practical screening protocol in chili peppers for aphids resistance in the tropical areas. Three no-choice test methods i.e., seedling cage, detached leaf, and clip cage tests have been developed. The experiment was conducted in a randomized complete block design (RCBD) with four replications in a greenhouse at the Gunung Putri, Bogor, West Java, Indonesia. Seven chili pepper genotypes belong to the species Capsicum annuum L. provided by the Department of Agronomy and Horticulture, IPB University, Bogor, Indonesia were used in this study. Chili pepper resistance to aphids was observed through the number of aphids progeny, and aphids fecundity among the genotypes. Two chili genotypes consistently showed low infestation while other genotypes showed the highest infestation with three screening methods. All the methods have a high heritability value (90%–91%), indicating that the evaluated chili genotypes could be used to determine effective screening methods. The correlation between the detached leaf and clip cage tests was significant (r = 0.84, P ≤ 0.05). Therefore, the clip cage test could be used as a reliable and practical screening test for the assay of chili peppers resistance to CA infestation. These information will be helpful in the development of aphid resistant cultivars in the future.