Life Table Parameters of Tetranychus merganser Boudreaux (Acari: Tetranychidae) on Five Host Plants.

The quality of the host plant affects the life history parameters of tetranychid mites. The biology and fertility life tables of Tetranychus merganser on five host plants (Carica papaya, Phaseolus vulgaris, Capsicum annuum var. glabriusculum, Helietta parvifolia, and Rosa hybrida) were assessed under laboratory conditions at 28 ± 1 °C and 70-80% relative humidity (RH) with a photoperiod of 12:12 h (L:D). The development period of immature females differed among the tested host plants and ranged from 9.32 days on P. vulgaris to 11.34 days on H. parvifolia. For immature males, it ranged from 9.25 days on P. vulgaris to 11.50 days on H. parvifolia. The female survival rate varied from 53.97% on H. parvifolia to 94.74% on P. vulgaris. The highest total fecundity rate was recorded on P. vulgaris (125.40 eggs/female) and the lowest on H. parvifolia (43.92 eggs/female). The intrinsic rate of increase (rm) varied from 0.271 (H. parvifolia) to 0.391 (P. vulgaris). The net reproductive rate (RO) was higher on P. vulgaris than on the other host plants. The longest mean generation time (GT) was calculated on C. annuum var. glabriusculum and the shortest on Rosa hybrida. The demographic parameters suggest the unsuitability of H. parvifolia as the host for the development of red spider mites, and the best performance of T. merganser was on P. vulgaris.

The Resistance of Seven Host Plants to Tetranychus merganser Boudreaux (Acari: Tetranychidae).

Red spider mites, Tetranychus merganser Boudreaux (Acari: Tetranychidae), is an agricultural pest that causes economic losses in papaya and nopal crops in Mexico. The aim of this research was to assess antibiosis and antixenosis as resistance mechanisms in seven host plants (Thevetia ahouai, Carica papaya, Phaseolus vulgaris, Moringa oleifera, Pittosporum tobira, Helietta parvifolia, Capsicum annuum var. glabriusculum) to red spider mites. Antixenosis was evaluated by non-preference for oviposition and feeding, antibiosis by infinitesimal rate of increase, finite rate of increase and doubling time, and the percentage of spider mites mortality. Oviposition and damage by feeding of T. merganser were significantly greater on C. papaya than on the other host plants. The growth rate of the spider mite was significantly lower in P. tobira and T. ahouai than in the other host plants. The percentage of hatched eggs of T. merganser was significantly higher in P. vulgaris than in the other plant species. Based on the demographic parameters, survival, food intake, and oviposition, these results indicated that compared with C. papaya, P. tobira and T. ahouai were more resistant. These results may be due to the fact that they were plants species of different families. The resistant plants can be studied as alternatives in the management of T. merganser.

Bioacaricidal Potential of Moringa oleifera Ethanol Extract for Tetranychus merganser Boudreaux (Acari: Tetranychidae) Control.

The Tetranychidae family includes mites causing severe damage to agricultural fields. The red spider mite, Tetranychus merganser Boudreaux (Acari: Tetranychidae), causes severe damage to several plant species grown as cash crops. Current red spider mite control depends mainly on chemical insecticides. There is a need for alternate control measures that are environmentally friendlier than chemical pesticides. The aim of the study was to assess the effects of Moringa oleifera leaf ethanolic extract at different concentrations (0.1, 0.5, 1, 5, 10, 15, and 20% (v/v)) against T. merganser females. Such effects can serve as a basis to include this compound in integrated pest management programs for the control of red spider mites. Mites treated with 20% (v/v) killed 86.67%, 13.70%, and 96.30% at 24, 48, and 72 h, respectively, as compared to the control treatment. Oviposition, egg hatching, and the damage caused by red spider mites were all reduced at high concentrations. Moringa oleifera leaf ethanolic extract can be used as a powerful bioacaricide for the control of T. merganser.

RoCoLe: A robusta coffee leaf images dataset for evaluation of machine learning based methods in plant diseases recognition.

In this article we introduce a robusta coffee leaf images dataset called RoCoLe. The dataset contains 1560 leaf images with visible red mites and spots (denoting coffee leaf rust presence) for infection cases and images without such structures for healthy cases. In addition, the data set includes annotations regarding objects (leaves), state (healthy and unhealthy) and the severity of disease (leaf area with spots). Images were all obtained in real-world conditions in the same coffee plants field using a smartphone camera. RoCoLe data set facilitates the evaluation of the performance of machine learning algorithms used in image segmentation and classification problems related to plant diseases recognition. The current dataset is freely and publicly available at https://doi.org/10.17632/c5yvn32dzg.2.

Peanut cultivars display susceptibility by triggering outbreaks of Tetranychus ogmophallos (Acari: Tetranychidae).

The peanut red spider mite, Tetranychus ogmophallos Ferreira and Flechtmann (Acari: Tetranychidae), is an important pest of peanut in Brazil and is considered a quarantine pest in other countries. This study investigates the development, reproduction, survival and life table parameters of T. ogmophallos on five peanut cultivars-three with high levels of oleic acid [high oleic] and recently released: Granoleico, IAC OL 3 and IAC 503; and two regular and previously used by farmers: Runner IAC 886, IAC Tatu ST 3-and two breeding lines (L. 8008 and L. 322) in the growth chamber. There were differences between the developmental times of all immature stages, the oviposition period, fecundity and adult longevity of T. ogmophallos reared on the peanut cultivars and breeding lines. The longest duration of the immature stage and lowest fecundity occurred on cultivars Granoleico and Runner IAC 886, and breeding line L. 322, which also displayed the lowest intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) and the shortest mean generation time (T). The highest fitness occurred on the IAC Tatu ST, IAC OL 3, IAC 503 and L. 8008. Our study shows that peanut cultivars belonging to the group with high oleic trait and recently released (IAC OL 3 and IAC 503) are susceptible to T. ogmophallos, except Granoleico, which is resistant. The regular and previously used cultivar Runner IAC 886 and breeding line L. 322 are resistant to the peanut red spider mite.

Population performance of Tetranychus evansi (Acari: Tetranychidae) on African tomato varieties and wild tomato genotypes.

The tomato red spider mite, Tetranychus evansi Baker & Pritchard, is one of the main pests of the tomato crop in several countries, mainly in Africa, where it can reduce tomato yield by up to 90%. The biotic potential of this mite is high and its control is difficult because of low efficiency of chemicals used and the rapid development of resistance to acaricides. We used the two-sex life table to evaluate the effect of two wild tomato genotypes (PI134417 and PI134418) and five tomato varieties widely grown in Benin (Kekefo, Akikon, TLCV15, Tounvi, and TOML4) on demographic characteristics of T. evansi under laboratory conditions. Tetranychus evansi did not develop on the genotypes PI134417 and PI134418, indicating their resistance to this mite. Developmental time of immature stages and female longevity were significantly higher on TLCV15 and Kekefo. Fecundity, net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) of T. evansi on the African varieties were not statistically different among varieties. Generation time (T) was shorter on TOML4 than on TLCV15 and Tounvi. Thus, efforts should be made to prospect varieties with resistance characteristics or to develop other control means, to reduce the use of pesticides to control T. evansi in Africa.

Influência da teia de Oligonychus ilicis (McGregor) (Acari: Tetranychidae) sobre os fitoseídeos predadores associados / Influence of the webbing produced by Oligonychus ilicis (McGregor) (Acari: Tetranychidae) on associated predatory phytoseiids

Oligonychus ilicis (McGregor) is among those mite species that can cause damage to coffee plants (Coffea spp.). Species of Phytoseiidae acari are considered the most important and studied predatory mites. The objective of this study was to evaluate the effects of the webbing produced by O.ilicis on its predation by females of the phytoseiids Iphiseiodes zuluagai Denmark & Muma, Euseius citrifolius Denmark & Muma and Amblyseius herbicolus (Chant). Four bioassays were conducted, with three treatments and ten replicates. Each replicate consisted of 25 O.ilicis per experimental unit (a leaf disc of Coffea arabica) according to the tested developmental stage, in independent experiments. To spin the web, 15 adult females were put on each experimental unit for 24h; females were then removed, leaving only the web, and predators and prey to be tested were introduced. Predation was assessed after 24h. In the presence of webbing, the consumption of eggs, larvae and nymphs by I.zuluagai and eggs and larvae by E.citrifolius was lower. For A.herbicolus, egg predation was lower, but larval predation did not vary significantly and predation of nymphs and adults was higher in the presence of webbing. Predators as a whole were more efficient consuming larvae regardless of the presence of webbing. Considering the stages of O.ilicis altogether, webbing reduced the predation potential of I.zuluagai and E. citrifolius, but not of A. herbicolus.

Biologia e tabela de vida de Tetranychus desertorum (Acari: Tetranychidae) sobre folhas de feijão (Phaseolus vulgaris)

Biological aspects and life table of the red spider mite, Tetranychus desertorum Banks, 1900, were studied on leaf discs of kidney bean (Phaseolus vulgaris Linnaeus) cultivar "Tacarigua" under laboratory conditions (28 ± 2ºC, 70 ± 10% R.H. and 12:12h). Our results showed that total developmental time was 6.8 days for females, with partial duration of immature stages corresponding to 3.8, 1.4, 1.0 and 0.7 for egg, larva, protonymph and deutonymph, respectively. Preoviposition, oviposition and postoviposition periods were 1.1, 8.4 and 1.3 days, respectively; and the higher mean fecundity (6.93 eggs/female/day) was observed on day 4. Female mean longevity was 10 days. The life table parameters recorded were: net reproduction rate (Ro) = 41.10 individuals; generation time (T) = 11.15 days; intrinsic natural growth (r m) = 0.144 individuals/female/day, and finite natural increase rate () = 1.155 individuals/female. Our findings could be a basis for further studies devoted to determine damage and control strategies for T. desertorum on kidney bean crops.

Biologia e tabela de vida de Tetranychus desertorum (Acari: Tetranychidae) sobre folhas de feijão (Phaseolus vulgaris)

Biological aspects and life table of the red spider mite, Tetranychus desertorum Banks, 1900, were studied on leaf discs of kidney bean (Phaseolus vulgaris Linnaeus) cultivar "Tacarigua" under laboratory conditions (28 ± 2ºC, 70 ± 10% R.H. and 12:12h). Our results showed that total developmental time was 6.8 days for females, with partial duration of immature stages corresponding to 3.8, 1.4, 1.0 and 0.7 for egg, larva, protonymph and deutonymph, respectively. Preoviposition, oviposition and postoviposition periods were 1.1, 8.4 and 1.3 days, respectively; and the higher mean fecundity (6.93 eggs/female/day) was observed on day 4. Female mean longevity was 10 days. The life table parameters recorded were: net reproduction rate (Ro) = 41.10 individuals; generation time (T) = 11.15 days; intrinsic natural growth (r m) = 0.144 individuals/female/day, and finite natural increase rate () = 1.155 individuals/female. Our findings could be a basis for further studies devoted to determine damage and control strategies for T. desertorum on kidney bean crops.

Biologia e tabela de vida de Tetranychus desertorum (Acari: Tetranychidae) sobre folhas de feijão (Phaseolus vulgaris)

Biological aspects and life table of the red spider mite, Tetranychus desertorum Banks, 1900, were studied on leaf discs of kidney bean (Phaseolus vulgaris Linnaeus) cultivar "Tacarigua" under laboratory conditions (28 ± 2ºC, 70 ± 10% R.H. and 12:12h). Our results showed that total developmental time was 6.8 days for females, with partial duration of immature stages corresponding to 3.8, 1.4, 1.0 and 0.7 for egg, larva, protonymph and deutonymph, respectively. Preoviposition, oviposition and postoviposition periods were 1.1, 8.4 and 1.3 days, respectively; and the higher mean fecundity (6.93 eggs/female/day) was observed on day 4. Female mean longevity was 10 days. The life table parameters recorded were: net reproduction rate (Ro) = 41.10 individuals; generation time (T) = 11.15 days; intrinsic natural growth (r m) = 0.144 individuals/female/day, and finite natural increase rate () = 1.155 individuals/female. Our findings could be a basis for further studies devoted to determine damage and control strategies for T. desertorum on kidney bean crops.

Influência da infestação de oligonychus ilicis (mcgregor, 1917) (acari: tetranychidae) sobre a taxa de fotossíntese potencial de folhas de cafeeiro

ABSTRACT Oligonychus ilicis (McGregor, 1917), is one of the main phytophagous mites of the coffee plant ( Coffea spp.), although it is not reported among the primary pests. They live on the upper surface of the leaves, puncturing the epidermis and mesophyll cells to absorb and feed on the extravasated cellular content. In consequence, the leaves lose their natural shine and become tan. The objective of this work was to quantify the photosynthetic rate of coffee-plant leaves presenting different infestation levels of O. ilicis. The study was carried out in potted three-year-old coffee plants ( Coffea arabica L., Catuaí cultivar), kept in a greenhouse. Infestations were accomplished at five different levels (0, 15, 30, 60 and 120 adult mite females/leaf), with mites coming from a stock rearing, on leaves of the third pair starting from the apex and totally expanded, located in branches from the middle third of the plant, with five repetitions. The potential photosynthesis was measured through the photosynthetic oxygen produced, using an oxygen monitor with a Clark type electrode coupled to a CB1 electric flow control box. The evaluations were made 7 and 21 days after the infestation with the mites, and the data obtained were submitted to regression analysis. There was a negative correlation between levels of infestation and potential photosynthesis, whereas at levels 15, 30, 60 and 120 mites/leaf, the photosynthetic rates were reduced in relation to the control treatment, in 37.2, 38.7; 46.0 and 50.1% respectively.

RESUMO Oligonychus ilicis (McGregor, 1917) é um dos principais ácaros fitófagos do cafeeiro ( Coffea spp.), embora não esteja relacionado entre as pragas primárias. Esses ácaros vivem na superfície superior das folhas e, para se alimentar, perfuram as células da epiderme e do mesófilo e absorvem o conteúdo celular extravasado. Em consequência, as folhas perdem o brilho natural e tornam-se bronzeadas. O objetivo deste trabalho foi quantificar a taxa de fotossíntese de folhas de cafeeiro apresentando diferentes níveis de infestação de O. ilicis. O estudo foi realizado em plantas de cafeeiro (Coffea arabica L., cultivar Catuaí) envasadas e com três anos de idade, mantidas em casa de vegetação. Foram realizadas infestações em cinco diferentes níveis (0, 15, 30, 60 e 120 fêmeas adultas do ácaro/folha), com ácaros provenientes da criação de manutenção, em folhas do terceiro par, a partir do ápice e totalmente expandidas, localizadas em ramos do terço médio da planta, com cinco repetições. A medição da fotossíntese potencial foi realizada por meio do oxigênio fotossintético produzido, utilizando-se de um monitor de oxigênio com eletrodo tipo Clark acoplado a uma caixa de controle de fluxo elétrico CB1. As avaliações foram realizadas 7 e 21 dias após a infestação com os ácaros, e os dados obtidos foram submetidos a uma análise de regressão. Houve correlação negativa entre os diferentes níveis de infestação e a fotossíntese potencial, sendo que, nos níveis 15, 30, 60 e 120 ácaros/folha, as taxas de fotossíntese foram reduzidas, em relação ao tratamento-testemunha, em 37,2; 38,7; 46,0 e 50,1%, respectivamente.