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The sweet potato (cotton) whitefly Bemisia tabaci is a major agricultural pest in various fields and vegetable crops worldwide. It causes extensive damage by direct feeding on plants, reducing quality, secreting honeydew and transmitting plant viruses. B. tabaci is known for its genetic diversity and considered a complex of biotypes or, as suggested, a complex of distinct cryptic species. Management of whiteflies relies mainly on the use of insecticides; however, its ability to develop resistance to major insecticide classes creates a serious challenge to farmers and pest control specialists. Among the cryptic species of B. tabaci , MED is considered more resistant than the MEAM1 to insecticides such as pyriproxyfen and neonicotinoids; however, in recent years there are other species of B. tabaci including MEAM1, Asia I and Asia II-1 that have developed high resistance to various groups of insecticides. Advanced methods based on molecular and gene sequence data obtained from resistant and susceptible field-collected B. tabaci populations resulted in a better understanding of resistance mechanisms in this pest. Several components of IPM-IRM (Integrated Pest Management-Insecticide Resistance Management) programs such as selective and biorational insecticides, insecticide rotation with different modes of action and nonchemical control methods are among the countermeasures of insecticide resistance management for this pest. In the current review, we concentrate on insecticide resistance and resistance management of B. tabaci, focusing on reports published mainly over the past 10 years.

ContextAfrican production landscapes are diverse, with multiple cassava cultivars grown in small patches amongst a diversity of other crops. Studies on how diverse smallholder landscapes impact herbivore pest outbreak risk have not been carried out in sub-Saharan Africa.ObjectivesBemisia tabaci is a cryptic pest species complex that cause damage to cassava through feeding and vectoring plant-virus diseases and are known to reach very high densities in certain contexts. However, the factors driving this phenomenon are unclear.MethodsBemisia density data in cassava across a large number of sites representing a geographic gradient across Uganda, Tanzania and Malawi were collected. We tested whether in-field or landscape factors associated with land-use patterns underpinned Bemisia density variability and parasitism.ResultsWe found the B. tabaci SSA1 species dominated our study sites, although other species were also common in some cassava fields. Factors associated with the surrounding landscape were unimportant for explaining variability in adult density, but the in-field variables of cassava age and cultivar were very important. The density of nymphs and the parasitism of nymphs was heavily influenced by a diversity of landscape factors surrounding the field, including the size of focal cassava field, and area of cassava in the landscape. However, unlike the trend from many other studies on drivers of natural enemy populations, this pattern was not solely related to the amount of non-crop vegetation, or the diversity of crops grown in the landscape.ConclusionsOur findings provide management options to reduce whitefly abundance, including describing the characteristics of landscapes with high parasitism. The choice of cassava cultivar by the farmer is critical to reduce whitefly outbreak risk at the landscape-scale.

Eggplant (Solanum melongena L.) is an important Indonesian crop increasingly threatened by begomoviruses that reduce yield and quality. Transmitted persistently by the whitefly Bemisia tabaci, these viruses are genetically diverse and often occur in mixed infections, intensifying disease severity and complicating control. This study aimed to identify begomovirus species infecting eggplant, determine their geographic distribution and dominance, and characterize the associated B. tabaci biotypes across major eggplant-producing regions of Java, Indonesia. Field surveys were conducted in five provinces—Banten, West Java, Central Java, Yogyakarta, and East Java—covering 30 lowland and 15 highland sites. From each site, 20 symptomatic plants were collected for molecular analysis, while disease incidence (DI) and severity (DS) were assessed from 200 plants. Across 45 sites, mean DI and DS reached 54.0% and 32.7% in lowlands and 34.8% and 26.8% in highlands, respectively. PCR amplification and sequencing confirmed three begomovirus species: Tomato yellow leaf curl Kanchanaburi virus (TYLCKaV), Pepper yellow leaf curl Indonesia virus (PepYLCIV), and Tomato leaf curl New Delhi virus (ToLCNDV). TYLCKaV was the most prevalent, occurring alone or in combination with PepYLCIV, particularly in lowlands, while ToLCNDV occurred at low frequencies, mainly in mixed infections. Four B. tabaci biotypes (A, B, Q, and AN) were detected, with biotype A dominating in lowlands and Q prevailing in highlands. This study provides the first island-wide molecular mapping of begomovirus species and B. tabaci biotypes infecting eggplant in Indonesia and elucidates the complex virus–vector interactions that shape eggplant disease epidemiology in tropical Asia.

In China, Tomato chlorosis virus (ToCV) and Tomato yellow leaf curl virus (TYLCV) are widely present in tomato plants. The epidemiology of these viruses is intimately associated with their vector, the whitefly ( Bemisia tabaci MED). However, how a ToCV+TYLCV mixed infection affects viral acquisition by their vector remains unknown. In this study, we examined the growth parameters of tomato seedlings, including disease symptoms and the heights and weights of non-infected, singly infected and mixed infected tomato plants. Additionally, the spatio-temporal dynamics of the viruses in tomato plants, and the viral acquisition and transmission by B. tabaci MED, were determined. The results demonstrated that: (i) ToCV+TYLCV mixed infections induced tomato disease synergism, resulting in a high disease severity index and decreased stem heights and weights; (ii) as the disease progressed, TYLCV accumulated more in upper leaves of TYLCV-infected tomato plants than in lower leaves, whereas ToCV accumulated less in upper leaves of ToCV-infected tomato plants than in lower leaves; (iii) viral accumulation in ToCV+TYLCV mixed infected plants was greater than in singly infected plants; and (iv) B. tabaci MED appeared to have a greater TYLCV, but a lower ToCV, acquisition rate from mixed infected plants compared with singly infected plants. However, mixed infections did not affect transmission by whiteflies. Thus, ToCV+TYLCV mixed infections may induce synergistic disease effects in tomato plants.

The whitefly, Bemisia tabaci MEAM1 Gennadius causes serious losses to Florida vegetable and ornamental production. In 2019, a maximum dose bioassay was administered to 20 field populations of B. tabaci MEAM1 collected from various economic and weed hosts across south Florida to assess insecticide efficacy. The maximum dose bioassay tests the top labeled rate of the insecticide against B. tabaci adults on treated cotton leaves in a Petri dish over a 72-h period. A susceptible laboratory colony of B. tabaci MEAM1 and a colony of B. tabaci MED were also tested. Survival over 72 h was used to produce an area under the maximum dose curve, which was used to compare insecticide effects on different populations. Overall, imidacloprid demonstrated the poorest efficacy, dinotefuran and flupyradifurone were the most effective, and bifenthrin, cyantraniliprole, and thiamethoxam tended to group together, providing intermediate control. Across populations tested, survival in whitefly adults treated with dinotefuran was 50% lower than whiteflies treated with imidacloprid, about 33% lower than whiteflies treated with thiamethoxam, bifenthrin, and cyantraniliprole, and 10% lower than whiteflies treated with flupyradifurone. Efficacy of bifenthrin was less than imidacloprid on some populations, particularly from the Homestead area. Imidacloprid and thiamethoxam had no effect on mortality of the MED population when it was tested after 22 mo in culture without exposure to insecticides, although 7 mo later, these materials resulted in some mortality for the MED population.

The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) MEAM1, is considered a serious pest of horticultural and many other crops. While eggplant (Solanum melongena) is one of the most favored host plants, the whiteflies exhibit preferences among different varieties. We hypothesized that certain morphological leaf characteristics of different varieties, like leaf trichome density, trichome length, leaf lamina thickness and leaf color, may affect whitefly landing, feeding and oviposition. In this study, we investigated the variation in leaf morphological characters among selected eggplant varieties and evaluated the effect of these leaf characteristics in rendering eggplant varieties either susceptible or resistant to B. tabaci. We evaluated eight eggplant varieties in choice feeding tests, and we found that the varieties JinSheng Zilongchangqie (JSZ) and H149 were the highly preferred varieties with the highest numbers of whitefly adults and eggs. Significantly lower numbers of whitefly adult eggs were found on the resistant variety Tuo Lu Bamu (TLB). The varieties JinGuangbo Luqie (JGL), JinGuangbo Ziquanqie (JGZ), DaYang Ziguanqie (DYZ), QinXing Ziguanqie (QXZ), and QinXing Niuxinqie (QXN) were moderately favored by B. tabaci. Leaf trichome density, trichome length and leaf lamina thickness were positively correlated with numbers of whitefly adults and eggs. B. tabaci was less attracted to the leaves that reflect long and middle wavelength light (higher R and G values) than to the bright green leaves (medium G value), but the short wavelength light (higher B value) had no significant effect on whitefly preference. The degree of hue had a positive effect, and saturation and brightness had a negative effect on whitefly attraction.

Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) is a significant pest that damages a wide range of high-value vegetable crops in south Florida. This pest has demonstrated the ability to develop resistance to various insecticide groups worldwide. Monitoring the resistance levels of MEAM1 populations and maintaining baseline susceptibility data are crucial for the long-term effectiveness of insecticide management strategies. We conducted serial dilution bioassays on 15 field populations of MEAM1 collected in south Florida to assess their resistance to 4 key insecticides: afidopyropen, cyantraniliprole, dinotefuran, and flupyradifurone.To quantify resistance levels, resistance ratios (RR) were generated by comparing the LC50 values of field populations to those of a known susceptible MEAM1 colony reared in the laboratory. Our findings reveal that all field-collected populations were susceptible to dinotefuran (RR 1–8) and flupyradifurone (RR 2–8). While over 80% of the populations tested were susceptible to afidopyropen (RR 1–9), 2 populations exhibited low (RR 38) and moderate resistance (RR 51), respectively. In contrast, most of the populations (57%) showed low to moderate resistance to cyantraniliprole (RR 21–78), and the remaining populations were susceptible (RR 3–10). The 2 populations with resistance to afidopyropen also exhibited moderate resistance to cyantraniliprole. Further research in this direction can aid in refining insecticide resistance management programs in Florida and other regions where B. tabaci MEAM1 is a major pest. Exploring the implications of these findings will be essential for insecticide use and integrated pest management strategies in south Florida.

Host plant relationships of Australian native and invasive whitefly species in the Bemisia tabaci species complex, namely AUSI and AUSII and Bemisia argentifolii (also called B. tabaci Middle East-Asia Minor 1 (MEAM1), were investigated with three approaches: ecologically in the field with surveys, experimentally in the laboratory, and using population genetics to assess any host-associated differentiation within whitefly species. AUSII and B. argentifolii were collected from various host plant species to test for gene flow using microsatellite genotyping. Neither species showed evidence of population structuring associated with host plant species. Host plant testing in the laboratory showed that only some host plants are reproductive hosts for these three whitefly species. Most individuals of all three species settled on tomato over the other host plant species in a cage with several host species presented simultaneously. Nevertheless, tomato was not a reproductive host for AUSI, and cassava did not support adult survival or nymphal production in any species. AUSI reproduced successfully on cotton, chia, and golden crownbeard. AUSII reproduced best on chia, followed by golden crownbeard, cotton, and tomato . Bemisia argentifolii reproduced well on tomato, followed by cotton, chia, and golden crownbeard. In summary, host plant testing supported the hypothesis that AUSI, AUSII, and B. argentifolii have different host plant relationships from one another and confirmed that the invasive B. argentifolii can use more host plant species for reproduction than the indigenous Australian species. Discrete host associations across cryptic species complexes are likely to be common amongst herbivorous insects.

Fruit processing waste, such as kernels (endocarp + seed) of avocado [ Persea americana Mill. (Lauraceae)], could be used as raw material in the preparation of botanical insecticides. In light of this potential, this study assessed the insecticidal action of extracts and fractions from kernels of two avocado cultivars (Breda and Margarida) on Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B, an important pest species in tropical conditions. Ethanolic and aqueous extracts prepared from kernels of P. americana , regardless of the plant cultivar used, caused promising insecticidal activity to whitefly nymphs. Based on yield in crude extracts [10.32 and 9.85% (w/w), respectively, for cultivars Breda and Margarida], on the bioassay results with crude extracts and on the chemical profiles, the ethanolic extract of kernels of P. americana cv. Breda was chose for the continuation of the study. Thus, the ethanolic extract of kernels of cv. Breda (LC 50  = 197.84 ppm and LC 90  = 567.19 ppm) was selected and subjected to fractionation by the liquid-liquid partition technique. The hexane and dichloromethane fractions of this extract caused significant mortality of nymphs. The analysis using the ultraviolet (UV) and hydrogen nuclear magnetic resonance ( 1 H NMR) showed the presence of long-chain aliphatic compounds (alkanols or acetogenins of Lauraceae), alkylfurans (or avocadofurans), and unsaturated fatty acids in these fractions, which are possibly related to bioactivity observed in B. tabaci , besides saccharides. The results show that kernels of P. americana are promising sources of compounds with insecticidal action for the control of B. tabaci biotype B, a great opportunity to transform environmental problems into eco-friendly solutions to agriculture.